how to debug python application crashed occasionally
Hello recently, I met a problem with one python application running with python2.5 | debian/lenny adm64 system: it crashed occasionally in our production environment. The problem started to happen just after we upgraded the python application from python2.4 | debian/etch amd64. after configuring the system to enable core dump & debugging with the core dumps by following the guide line from http://wiki.python.org/moin/DebuggingWithGdb, I became more confused about that. The first crash case was happening in calling python-xml module, which is claimed as a pure python module, and it's not supposed to crash python interpreter. because the python application is relatively a big one, I can not show u guys the exact source code related with the crash, but only the piece of python modules. GDB shows it's crashed at string join operation: #0 string_join (self=0x7f7075baf030, orig=) at ../Objects/stringobject.c:1795 1795../Objects/stringobject.c: No such file or directory. in ../Objects/stringobject.c and pystack macro shows the details: gdb) pystack /usr/lib/python2.5/StringIO.py (271): getvalue /usr/lib/python2.5/site-packages/_xmlplus/dom/minidom.py (62): toprettyxml /usr/lib/python2.5/site-packages/_xmlplus/dom/minidom.py (47): toxml at that time, we also found python-xml module has performance issue for our application, so we decided to use python-lxml to replace python-xml. After that replacement, the crash was gone. That's a bit weird for me, but anyway, it's gone. Unfortunately, another two 'kinds' of crashes happening after that, and the core dumps show they are not related with the replacement. One is crashed with "Program terminated with signal 11", and the pystack macro shows it's crashed at calling the built-in id() function. #0 visit_decref (op=0x20200a3e22726574, data=0x0) at ../Modules/ gcmodule.c:270 270 ../Modules/gcmodule.c: No such file or directory. in ../Modules/gcmodule.c Another is crashed with "Program terminated with signal 7", and the pystack macro shows it's crashed at the exactly same operation (string join) as the first one (python-xml), but in different library python- simplejson: #0 string_join (self=0x7f5149877030, orig=) at ../Objects/stringobject.c:1795 1795../Objects/stringobject.c: No such file or directory. in ../Objects/stringobject.c (gdb) pystack /var/lib/python-support/python2.5/simplejson/encoder.py (367): encode /var/lib/python-support/python2.5/simplejson/__init__.py (243): dumps I'm not good at using gdb & C programming, then I tried some other ways to dig further: * get the source code of python2.5, but can not figure out the crash reason :( * since Debian distribution provides python-dbg package, and I tried to use python2.5-dbg interpreter, but not the python2.5, so that I can get more debug information in the core dump file. Unfortunately, my python application is using a bunch of C modules, and not all of them provides -dbg package in Debian/Lenny. So it still doesn't make any progress yet. I will be really appreciated if somebody can help me about how to debug the python crashes. Thanks in advance! BR Jacky Wang -- http://mail.python.org/mailman/listinfo/python-list
Re: Japanese (speaking) developer needed for a bit of regex magic
On Tue, Apr 20, 2010 at 9:52 PM, Ben Finney wrote: > Sebastian writes: >> All locales return error messages in English. Only the Japanese uses >> Japanese which my regular expressions cannot handle at the moment. > > What exactly are you expecting to happen, and what exactly happens > instead? > > General advice with character sets in Python apply: always explicitly > declare the encoding of input, then decode to Unicode interally as early > as possible, and process all text that way. Only fix into an encoding > when it's time to output. I think he has more of a *literal* language problem: He doesn't know Japanese and thus can't read the Japanese error message in order to develop a regex for it. I assume there's some reason he can't just do a blind equality test on the error message string(s). Cheers, Chris -- http://blog.rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
Re: python glibc crypt() function
luca72 wrote: > On 20 Apr, 19:38, Peter Otten <__pete...@web.de> wrote: >> luca72 wrote: >> > Hello i have to do this : >> > glibc crypt() function, using salt $1$abcdefgh$ >> >> > cryptPw = crypt(plainPw, "$1$abcdefgh$") > Thanks > The result is correct i obtain the same with ctypes and crypt module, > so i think that is better to use the crypt module is correct? Yes, use the crypt module. -- http://mail.python.org/mailman/listinfo/python-list
how does a queue stop the thread?
A simple thread pool example. My question is, since *MyThread.run* will loop endless, how does the thread know the time to quit? how does the *queue* notify the thread? is there any shared variables, like a *lock*? When I set daemon false, it stays in the loop, not quit any more. what's the role does the daemon state plays? code: import Queue import threading def do_some_thing(x): print int(x) class MyThread(threading.Thread): def __init__(self, queue): threading.Thread.__init__(self) self.queue = queue def run(self): while True: params = self.queue.get() do_some_thing(params) self.queue.task_done() q = Queue.Queue() for i in range(1, 5): t = MyThread(q) t.setDaemon(True) t.start() for x in range(10): q.put(x) q.join() -- http://mail.python.org/mailman/listinfo/python-list
error when printing a UTF-8 string (python 2.6.2)
Hello. I read a string from an utf-8 file: fichierLaTeX = codecs.open(sys.argv[1], "r", "utf-8") s = fichierLaTeX.read() fichierLaTeX.close() I can then print the string without error with 'print s'. Next I parse this string: def parser(s): i = 0 while i < len(s): if s[i:i+1] == '\\': i += 1 if s[i:i+1] == '\\': print "backslash" elif s[i:i+1] == '%': print "pourcentage" else: if estUnCaractere(s[i:i+1]): motcle = "" while estUnCaractere(s[i:i+1]): motcle += s[i:i+1] i += 1 print "mot-clé '"+motcle+"'" but when I run this code, I get this error: Traceback (most recent call last): File "./versOO.py", line 115, in parser(s) File "./versOO.py", line 105, in parser print "mot-clé '"+motcle+"'" UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 6: ordinal not in range(128) What must I do to solve this? Thanks! -- Fabrice DELENTE -- http://mail.python.org/mailman/listinfo/python-list
Re: Operations on sparse matrices
On 04/19/10 08:03, pp wrote: > I am currently dealing with sparse matrices and have doubts on whether > we can use > 1.) dot (for matrix multiplication) and inv (inverse) operations of > numpy on sparse matrices of CSR format. > I don't know of any use of the inverse of a sparse matrix. Note, in nearly all cases the inverse of a sparse matrix is a full matrix. Instead of inverting a matrix solve a linear system with that matrix. What do you need the inverse for? Helmut. -- Helmut Jarausch Lehrstuhl fuer Numerische Mathematik RWTH - Aachen University D 52056 Aachen, Germany -- http://mail.python.org/mailman/listinfo/python-list
Re: how does a queue stop the thread?
On Wed, Apr 21, 2010 at 1:38 PM, kaiix wrote: > A simple thread pool example. My question is, since *MyThread.run* > will loop endless, how does the thread know the time to quit? how does > the *queue* notify the thread? is there any shared variables, like a > *lock*? > > When I set daemon false, it stays in the loop, not quit any more. > what's the role does the daemon state plays? > Take a look at the documentation for the threading module here: http://docs.python.org/release/2.6/library/threading.html, and the discussion on daemon vs non-daemon threads here: http://blog.doughellmann.com/2008/01/pymotw-threading_13.html Basically, as long as at least one non-daemon thread is still running, your program will not exit. > -- regards, kushal -- http://mail.python.org/mailman/listinfo/python-list
Re: how does a queue stop the thread?
On Wed, Apr 21, 2010 at 1:50 PM, Kushal Kumaran wrote: > On Wed, Apr 21, 2010 at 1:38 PM, kaiix wrote: >> A simple thread pool example. My question is, since *MyThread.run* >> will loop endless, how does the thread know the time to quit? how does >> the *queue* notify the thread? is there any shared variables, like a >> *lock*? >> >> When I set daemon false, it stays in the loop, not quit any more. >> what's the role does the daemon state plays? >> > > Take a look at the documentation for the threading module here: > http://docs.python.org/release/2.6/library/threading.html, and the > discussion on daemon vs non-daemon threads here: > http://blog.doughellmann.com/2008/01/pymotw-threading_13.html > > Basically, as long as at least one non-daemon thread is still running, > your program will not exit. > >> > And I should have read your mail better. Take a look at the documentation of the task_done method: http://docs.python.org/library/queue.html -- regards, kushal -- http://mail.python.org/mailman/listinfo/python-list
Re: Write web apps in Python?
Bryan a écrit : I think I see what you mean Err... -- correct me if I'm wrong: You are, sorry !-) You want to keep complex application data structures around between requests. Nope. I want to keep all my settings parsed, my librairies loaded, all my connections opened etc. That is, all the time consuming stuff at app startup - which, with PHP, mostly happens for each and every request. PHP frameworks generally allow and encourage application code to be independent of the underlying plumbing. This is debatable at best. PHP code (except cli PHP code of course) is written without any care for persistent global state, concurrency issues, race conditions etc - because it's written with the idea that the code serving a request will be runned in total isolation. CGI heritage here, obviously. No, that's good web-app structure, regardless of language and server interface. If we keep persistent global state in a shared database rather than program variables, Err... Did you really read what you're answering too ??? Also, I never said this execution model was necessarily bad - just that it had pros *and* cons. And please note I'm not criticizing this design- just pointing one of it's consequences. Many large, sophisticated, high-volume web apps are in PHP. Did anyone pretend otherwise ? How about this howler: "The PHP execution model (mostly based on CGI FWIW) tends to be a bit unpractical for non-trivial applications". "tends to be a bit unpractical" != "doesn't work". Many large, sopĥisticated etc applications are written in C. Does that make C a practical application programming language ? Now I'm sorry to say that for quite a few "sophisticated" PHP apps I've seen (and eventually had to work on), the "startup" part - parsing the include files, configuration, establishing connections etc - took a good part of the total processing time. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it better to extend a class, or do something repetitious in the main part of a program?
On Apr 19, 3:45 pm, J wrote:
> First, before I get farther,
>
> Is there a way for theloggingmodule to natively handle lists and
> dict objects whenlogging?
>
> e.g. take this {'key1':'val1','key2':'val2'} and have it logged like this:
>
> INFO: key1: val1
> INFO: key2: val2
>
> If I pass the dict or list directly to the logger, it is logged the
> same as if you simply did this:
>
> mydict={1:1, 2:2}
> mylist=[1,2,3]
>
> print mydict
> print mylist
>
> >>> {1:1,2:2}
> >>> [1,2,3]
>
> It came up that I wanted to haveloggingpresent command line options
> from optparse if the log level was set to debug... so they'd look
> something like this in the output:
>
> debug: True
> sleep_time: 30
> log_file: /tmp/testlog
>
> So the options I've managed to work out are to either parse the list
> or dict object item by item and feed those items one at a time into
> the logger:
>
> for i in mylist:
> logging.info(i)
>
> Or to extend the StreamHandler class to handle this by creating a new
> report.msg...
>
> Then the discussion came up: which is better? To parse a dictionary
> or list in the main code and pass each item to the logger one at a
> time, or to extend the logger to handle it natively?
>
> Any thoughts on which is the more proper way to handle cases like this?
Since you want to have a specific output format for the logged
information, the best way to go would be to write your own Formatter
subclass, and check in its format() method whether you have lists/
dicts and then format them however you want into a string, and return
the appropriately formatted string from that method.
Regards,
Vinay Sajip
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Re: error when printing a UTF-8 string (python 2.6.2)
f...@slick.airforce-one.org wrote: > Hello. > > I read a string from an utf-8 file: > > fichierLaTeX = codecs.open(sys.argv[1], "r", "utf-8") > s = fichierLaTeX.read() > fichierLaTeX.close() > > I can then print the string without error with 'print s'. > > Next I parse this string: > > def parser(s): > i = 0 > while i < len(s): > if s[i:i+1] == '\\': >i += 1 >if s[i:i+1] == '\\': > print "backslash" >elif s[i:i+1] == '%': > print "pourcentage" >else: > if estUnCaractere(s[i:i+1]): > motcle = "" > while estUnCaractere(s[i:i+1]): > motcle += s[i:i+1] > i += 1 >print "mot-clé '"+motcle+"'" > > but when I run this code, I get this error: > > Traceback (most recent call last): > File "./versOO.py", line 115, in > parser(s) > File "./versOO.py", line 105, in parser > print "mot-clé '"+motcle+"'" > UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in > position 6: ordinal not in range(128) > > What must I do to solve this? >>> "mot-clé" + "mot-clé" 'mot-cl\xc3\xa9mot-cl\xc3\xa9' >>> u"mot-clé" + u"mot-clé" u'mot-cl\xe9mot-cl\xe9' >>> "mot-clé" + u"mot-clé" Traceback (most recent call last): File "", line 1, in UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 6: ordinal not in range(128) codecs.open().read() returns unicode, but your literals are all bytestrings. When you are mixing unicode and str Python tries to convert the bytestring to unicode using the ascii codec, and of course fails for non-ascii characters. Change your string literals to unicode by adding the u-prefix and you should be OK. Peter -- http://mail.python.org/mailman/listinfo/python-list
rfind bug ?
With the following code, I would expect a result of 5 !!
>>> a= 'word1 word2 word3'
>>> a.rfind(' ',7)
11
Is this a bug ?
thanks,
Stef
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Re: rfind bug ?
On Wed, Apr 21, 2010 at 1:51 AM, Stef Mientki wrote:
> With the following code, I would expect a result of 5 !!
>
a= 'word1 word2 word3'
a.rfind(' ',7)
> 11
>
> Is this a bug ?
No. Don't you think someone would have found such an obvious bug by now?
You want regular str.find(), which searches from left-to-right:
a= 'word1 word2 word3'
>>> a.find(' ')
5
str.rfind() is a variant of str.find() that searches from
right-to-left. The "r" is for "right".
Cheers,
Chris
--
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Re: rfind bug ?
On Wed, Apr 21, 2010 at 6:51 PM, Stef Mientki wrote:
>
> With the following code, I would expect a result of 5 !!
>
a= 'word1 word2 word3'
a.rfind(' ',7)
> 11
>
> Is this a bug ?
Python's documentation states:
| rfind(...)
| S.rfind(sub [,start [,end]]) -> int
|
| Return the highest index in S where substring sub is found,
| such that sub is contained within s[start:end]. Optional
| arguments start and end are interpreted as in slice notation.
|
| Return -1 on failure.
"Return the highest index in S"
I haven't looked at python's source code for the
str object, but perhaps this is exactly what it's
algorithm does!
cheers
James
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Re: rfind bug ?
Chris Rebert wrote:
[didn't see the original message]
> On Wed, Apr 21, 2010 at 1:51 AM, Stef Mientki
> wrote:
>> With the following code, I would expect a result of 5 !!
>>
> a= 'word1 word2 word3'
> a.rfind(' ',7)
>> 11
>>
>> Is this a bug ?
>
> No. Don't you think someone would have found such an obvious bug by now?
Indeed.
OP: you may be looking for
>>> a = "a bb ccc"
>>> a[::-1].find(" ")
3
Peter
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Re: error when printing a UTF-8 string (python 2.6.2)
> Change your string literals to unicode by adding the u-prefix and you should > be OK. Thanks, it solved the problem... for a while! I need now to know if s[i] gives the next byte or the next character, when I scan the string s. I've googled pages about python and unicode, but didn't find a solution to that. I scan the string read from the file char by char to construct s, but now get the same error when just trying 'print s'. Is there a way to tell python that all strings and characters are to be treated as UTF-8? I have LC_ALL=en_GB.utf-8 in my shell, but python does'nt seem to use this variable? Thanks! -- Fabrice DELENTE -- http://mail.python.org/mailman/listinfo/python-list
Re: Japanese (speaking) developer needed for a bit of regex magic
> General advice with character sets in Python apply: always explicitly > declare the encoding of input, then decode to Unicode interally as early > as possible, and process all text that way. Only fix into an encoding > when it's time to output. Maybe I was too vague when describing my problem. As Chris correctly guessed, I have a literal language problem. > > All locales return error messages in English. Only the Japanese uses > > Japanese which my regular expressions cannot handle at the moment. > > What exactly are you expecting to happen, and what exactly happens > instead? My regular expressions turn the Amazon error messages into Python exceptions. This works fine as long as they are in English: "??? is not a valid value for BrowseNodeId. Please change this value and retry your request.", for instance, will raise an InvalidParameterValue exception. However, the Japanese version returns the error message "??? は、BrowseNodeIdの値として無効です。値を変更してから、再度リクエストを実行してください。" which will not be successfully handled. This renders the my module pretty much useless for Japanese users. I'm was therefore wondering if someone with more knowledge of Japanese than me can have a look at my expressions. Maybe the Japanese messages are completely different... I have a collection of sample messages here (all files *-jp-*.xml): http://bitbucket.org/basti/python-amazon-product-api/src/tip/tests/2009-11-01/ Any help is appreciated! Cheers, Sebastian -- http://mail.python.org/mailman/listinfo/python-list
Re: error when printing a UTF-8 string (python 2.6.2)
On Wed, Apr 21, 2010 at 2:29 AM, wrote: >> Change your string literals to unicode by adding the u-prefix and you should >> be OK. > > Thanks, it solved the problem... for a while! > > I need now to know if s[i] gives the next byte or the next character, > when I scan the string s. I've googled pages about python and unicode, > but didn't find a solution to that. I scan the string read from the > file char by char to construct s, but now get the same error when just > trying 'print s'. Assuming s = fichierLaTeX.read() as from your code snippet, the next character. When in doubt, check what `type(s)` is; if it's , indices are in bytes; if it's , indices are in code points. Please give the full stack traceback for your error. Cheers, Chris -- http://blog.rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Code redundancy
Alan Harris-Reid wrote:
Jean-Michel Pichavant wrote:
Alan Harris-Reid wrote:
Hi,
During my Python (3.1) programming I often find myself having to
repeat code such as...
class1.attr1 = 1
class1.attr2 = 2
class1.attr3 = 3
class1.attr4 = 4
etc.
Is there any way to achieve the same result without having to repeat
the class1 prefix? Before Python my previous main language was
Visual Foxpro, which had the syntax...
with class1
.attr1 = 1
.attr2 = 2
.attr3 = 3
.attr4 = 4
etc.
endwith
Is there any equivalent to this in Python?
Any help would be appreciated.
Alan Harris-Reid
Hello,
Use an effective text editor, repeating stuff should not be a
problem. In a more general manner, avoid trying to speed your writing
while you should care speeding the reading.
Most of the tricks you could use will confuse the reader (unless the
reader is familiar with Visual foxpro).
Anyway,
for attrName, value in [
('attr1', 1),
('attr2', 2),
('attr3', 3),
]:
setattr(class1, attrName, value)
or
class Foo:
def __init__(self):
self.attr1=None
self.attr2=None
self.attr3=None
def set(self, *args, **kwargs):
for k in kwargs:
if hasattr(self, k):
setattr(self, k, kwargs[k])
else:
raise AttributeError('%s instance has no attribute "%s"' %
(self.__class__.__name__, k))
f = Foo()
f.set(attr1=25)
print f.__dict__
f.set(attr3=4, attr2=89)
print f.__dict__
f.set(bar= 8)
output:
{'attr2': None, 'attr3': None, 'attr1': 25}
{'attr2': 89, 'attr3': 4, 'attr1': 25}
AttributeError: Foo instance has no attribute "bar"
JM
Hi Jean-Michel,
Interesting solutions, but I think for the effort involved (and
readability) I'll stick to repeating the class.
Regards,
Alan
that's the way to go :)
JM
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Re: how does a queue stop the thread?
@kushal, thanks for your replies. before i wrote the email, i've already read the python docs carefully. i need the proof from code, i mean python source code. i tried to prove some of my assumptions that lead the loop quit, and i traced back to Queue.py, threading.py, dummy_thread.py, now i need some hints to help me understanding the sample from python source code. -- http://mail.python.org/mailman/listinfo/python-list
Re: Write web apps in Python?
On Wed, 2010-04-21 at 10:28 +0200, Bruno Desthuilliers wrote: > Bryan a écrit : > > > > I think I see what you mean > > Err... > > > -- correct me if I'm wrong: > > You are, sorry !-) > > > You want to > > keep complex application data structures around between requests. > > Nope. I want to keep all my settings parsed, Store them in the session. > my librairies loaded, Enable APC > all my connections opened etc. If you are talking about RDBMS connections, use persistent connections. Then you have everything you've asked for. > Now I'm sorry to say that for quite a few "sophisticated" PHP apps I've > seen (and eventually had to work on), the "startup" part - parsing the > include files, configuration, establishing connections etc - took a good > part of the total processing time. -- http://mail.python.org/mailman/listinfo/python-list
Re: rfind bug ?
Peter Otten <__pete...@web.de> writes:
> OP: you may be looking for
>
a = "a bb ccc"
a[::-1].find(" ")
> 3
But you should be aware of the effeciency implications of doing
this. a[::-1] constructs a new list. It's probably faster to do e.g.:
len(a) - a.rfind(..) - 1
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Re: deleting objects present in a list
(For some reason you posted your response before the message you were
replying to. That's called Top-posting, and is bad form on these
mailing lists)
Sandy wrote:
Thanks for the replies.
Terry,
What does 'immediately' mean? I did a small test and here are the
results.
import psutil
def testing():
class Object():
pass
l =}
apm =sutil.avail_phymem()/(1024*1024)
print 'Before creating objs: ' + repr(apm)
for i in xrange(50):
l.update({Object():1})
apm =sutil.avail_phymem()/(1024*1024)
print 'After creating objs: ' + repr(apm)
return l
def hello():
myl =esting()
apm =sutil.avail_phymem()/(1024*1024)
print 'Before deleting: ' + repr(apm)
del myl
# Here I want to delete the objects in the list
# deleting myl doesn't seem to change the memory
apm =sutil.avail_phymem()/(1024*1024)
print 'After deleting: ' + repr(apm)
if __name__ ='__main__':
hello()
OUTPUT:
Before creating objs: 2516L
After creating objs: 2418L
Before deleting: 2418L
After deleting: 2430L
In my original case the memory is not getting released even after long
time.
- dksr
On Apr 20, 8:44 pm, Terry Reedy wrote:
On 4/20/2010 3:21 PM, Sandy wrote:
Hi all,
I have large number of objects created and to handle them properly, I
store them in a list. How can I delete all of these objects (delete I
mean here is to remove the object from memory not just from list)?
I cannot use the list to iterate through the objects to delete them.
Because 'del' only reduces the reference count and as it is present in
the list it is not deleted. I cannot delete the list because I loose
control over the objects.
Deleting the list is the best you can do. If that deletes the last
reference, then the interpreter will delete the object when it feels
like it. For *current* CPython, this will be immediately. For other
implementations, whenever.
First, you're using some 3rd party library for measuring some kind of
memory usage. I'd guess you're probably using
http://code.google.com/p/psutil/ Since I'm not familiar with
how they derive these numbers, I can only make a good guess as to how
valid they are. And if avail_phymem refers to what its name implies,
it has little to do with Python. Python doesn't control physical
memory, only virtual.
So let's skip those numbers and talk about what CPython actually does.
As others have pointed out, other implementations will be different.
When you delete a large number of objects (which you can do with
myl=None), CPython may keep some of the memory under its own control for
reuse. A future object of the same size will fit nicely in the hole,
and that may be faster than calling free() and malloc() again.
When CPython calls free(), the C runtime library almost certainly keeps
the memory for reuse by subsequent calls to malloc(). Operating system
calls for allocating and freeing memory are (usually) done in larger,
fixed-size blocks. In Windows for example, the granularity is 4k or 64k
for the more efficient methods of memory allocation. Swapfile
allocation, for example, is always in 4k multiples. See function call
VirtualAlloc(). Anyway, if there's even a single allocated byte in a
block, it can't release the block. And searching for such blocks is slow.
When the operating system is told to free something, it usually does not
"free" physical memory immediately. In the case of Windows, it marks
the block as available, and eventually a daemon task will zero it. But
it could very well be "charged to" the current process until some other
process needs the physical memory. What it does do is free it from
virtual memory. But notice that Virtual memory is represented by a
swapfile on disk, and Windows doesn't support a file with gaps in it
(sparse allocation). So unless this particular allocation is at the end
of the file, the size isn't likely to go down.
If you really want to "observe" that the memory has been "released,"
I'd suggest calling a similar testing() function a second time, with
objects of the same size, and see whether the numbers get any worse.
I'd say they won't, at least not by much, assuming there's any validity
to this avail_phymem() function.
I also have to point out that using "del myl" is not necessary for
freeing up the memory. All that's necessary is for the myl name to stop
referring to the list, and the list will go away. So myl=42 will work
just as well.
HTH
DaveA
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shove does not store data as expected
Dear all,
I'm trying to use the shove module (http://pypi.python.org/pypi/shove)
for a simple script. The script read a CSV file ad store the data.
When I check the content of the "store" object (instance of Shove)
*before* I close it, the data are all there but when I close and re-
open it some data are lost. How it is possible? There is something
wrong in my code or I didn't understand how shove works?
Thanks in advance.
Here is a sample of my code:
DBNAME = "file://store.db"
csv_file ="test.csv"
cities = csv.reader(open(csv_file), delimiter=";")
store = Shove(DBNAME, compress=True)
for city,region,code in cities:
entry_list = store.setdefault(region, [])
data = 'just a sample'
entry = {city:data}
entry_list.append(entry)
print "Before closing"
for k,v in store.iteritems():
print "Key->", k
print "Value->", v
print ""
store.close()
store = Shove(DBNAME, compress=True)
print "After closing and re-opening"
for k,v in store.iteritems():
print "Key->", k
print "Value->", v
print ""
Here is the output
Before closing
Key-> Marche
Value-> [{'Ancona': 'just a sample'}, {'Ascoli Piceno': 'just a
sample'}]
Key-> Piemonte
Value-> [{'Alessandria': 'just a sample'}, {'Asti': 'just a sample'}]
Key-> Puglia
Value-> [{'Bari': 'just a sample'}, {'Barletta-Andria-Trani': 'just a
sample'}]
Key-> Valle d'Aosta
Value-> [{'Aosta': 'just a sample'}]
After closing and re-opening
Key-> Marche
Value-> [{'Ancona': 'just a sample'}]
Key-> Piemonte
Value-> [{'Alessandria': 'just a sample'}]
Key-> Puglia
Value-> [{'Bari': 'just a sample'}, {'Barletta-Andria-Trani': 'just a
sample'}]
Key-> Valle d'Aosta
Value-> [{'Aosta': 'just a sample'}]
Here is the content of the CSV file:
Alessandria;Piemonte;AL
Ancona;Marche;AN
Aosta;Valle d'Aosta;AO
Ascoli Piceno;Marche;AP
Asti;Piemonte;AT
Bari;Puglia;BA
Barletta-Andria-Trani;Puglia;BT
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Re: rfind bug ?
On 21-04-2010 10:56, Chris Rebert wrote:
> On Wed, Apr 21, 2010 at 1:51 AM, Stef Mientki wrote:
>
>> With the following code, I would expect a result of 5 !!
>>
>>
> a= 'word1 word2 word3'
> a.rfind(' ',7)
>
>> 11
>>
>> Is this a bug ?
>>
> No. Don't you think someone would have found such an obvious bug by now?
>
if it's not a bug,
then the start index has no meaning ...
... and some would call that a bug.
cheers,
Stef
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Re: rfind bug ?
Paul Rudin wrote:
> Peter Otten <__pete...@web.de> writes:
>
>
>> OP: you may be looking for
>>
> a = "a bb ccc"
> a[::-1].find(" ")
>> 3
>
>
> But you should be aware of the effeciency implications of doing
> this. a[::-1] constructs a new list.
A new string, yes.
> It's probably faster to do e.g.:
> len(a) - a.rfind(..) - 1
Yes, especially if the string is "long":
$ python -m timeit -s'a = "word1 word2 word3"' 'a[::-1].rfind(" ")'
100 loops, best of 3: 0.834 usec per loop
$ python -m timeit -s'a = "word1 word2 word3"*100' 'a[::-1].rfind(" ")'
10 loops, best of 3: 5.04 usec per loop
$ python -m timeit -s'a = "word1 word2 word3"' 'len(a)-a.rfind(" ")-1'
100 loops, best of 3: 0.587 usec per loop
$ python -m timeit -s'a = "word1 word2 word3"*100' 'len(a)-a.rfind(" ")-1'
100 loops, best of 3: 0.592 usec per loop
But be aware of the following difference:
>>> a[::-1].rfind("not there")
-1
>>> len(a) - a.rfind("not there") -1
8
Peter
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Re: how does a queue stop the thread?
On Wed, Apr 21, 2010 at 7:36 PM, kaiix wrote: > before i wrote the email, i've already read the python docs carefully. > i need the proof from code, i mean python source code. i tried to > prove some of my assumptions that lead the loop quit, and i traced > back to Queue.py, threading.py, dummy_thread.py, now i need some hints > to help me understanding the sample from python source code. You would need to look into the source code of python's builtin 'thread' module which is the low-level threading implementation used by python's 'threading' module (which is a wrapper atop this). 'threading' aside from everything else it does, really in the end calls thread.start_new_thread(...) cheers James -- http://mail.python.org/mailman/listinfo/python-list
Re: Write web apps in Python?
Bruno Desthuilliers writes: > Nope. I want to keep all my settings parsed, my librairies loaded, all > my connections opened etc. That is, all the time consuming stuff at > app startup - which, with PHP, mostly happens for each and every > request. I thought we have WSGI for this? Nothing stops a Python app from working like PHP. PHP has an advantage when you want to run mutually hostile apps in the same process (relevant if you're running ultra-cheap shared hosting and you want to put 1000 customers' virtual hosts in the same mod_php instance), but I don't think you're looking to do that. -- http://mail.python.org/mailman/listinfo/python-list
Re: Code redundancy
You can do something like this:
>>> class A(): pass
>>> inst=A()
>>> exec("""
... a=1
... b=2
... c=3
... d=4
... """) in inst.__dict__
>>> inst.a
1
>>>
This executes the Statement in the exec function and uses inst.__dict__
as namespace. But be aware, that this is not recommended. If you mess
with __dict__, you won't be able to replace it with some logic
(parameter) if you need to do something more than setting a variable.
Best
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Re: Write web apps in Python?
On Wed, Apr 21, 2010 at 2:33 AM, Adam Tauno Williams wrote: > On Wed, 2010-04-21 at 10:28 +0200, Bruno Desthuilliers wrote: >> Bryan a écrit : >> > >> > I think I see what you mean >> >> Err... >> >> > -- correct me if I'm wrong: >> >> You are, sorry !-) >> >> > You want to >> > keep complex application data structures around between requests. >> >> Nope. I want to keep all my settings parsed, > > Store them in the session. I don't think that makes sense. You still have to re-parse the settings upon starting each new session to store it in the session in the first place. Even then, you're suggesting needlessly keeping separate copies of the settings data for each session, going from O(1) to O(N) in space; that's rather wasteful. Cheers, Chris -- http://blog.rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
Re: rfind bug ?
Stef Mientki wrote:
On 21-04-2010 10:56, Chris Rebert wrote:
On Wed, Apr 21, 2010 at 1:51 AM, Stef Mientki wrote:
With the following code, I would expect a result of 5 !!
a= 'word1 word2 word3'
a.rfind(' ',7)
11
Is this a bug ?
No. Don't you think someone would have found such an obvious bug by now?
if it's not a bug,
then the start index has no meaning ...
... and some would call that a bug.
cheers,
Stef
a.rfind(' ', 12)
Out[12]: -1
looks like the start index has a meaning ...
JM
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Re: rfind bug ?
On Wed, Apr 21, 2010 at 2:59 AM, Stef Mientki wrote:
> On 21-04-2010 10:56, Chris Rebert wrote:
>> On Wed, Apr 21, 2010 at 1:51 AM, Stef Mientki wrote:
>>> With the following code, I would expect a result of 5 !!
>>>
>> a= 'word1 word2 word3'
>> a.rfind(' ',7)
>>
>>> 11
>>>
>>> Is this a bug ?
>>>
>> No. Don't you think someone would have found such an obvious bug by now?
>>
> if it's not a bug,
> then the start index has no meaning ...
> ... and some would call that a bug.
Ah, I neglected to take your use of .rfind()'s second parameter into account!
As can be interpolated from the part of the docs James quotes:
s.rfind(' ', 7) === s[7:].rfind(' ') + 7 # overlooking the 'not present' case
That is, the second parameter to .rfind(), namely `start`, is relative
to the *left* end of the string, not the right end. I can see how this
might be unintuitive, but it does make the API more uniform.
Cheers,
Chris
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Re: rfind bug ?
* Chris Rebert:
On Wed, Apr 21, 2010 at 2:59 AM, Stef Mientki wrote:
On 21-04-2010 10:56, Chris Rebert wrote:
On Wed, Apr 21, 2010 at 1:51 AM, Stef Mientki wrote:
With the following code, I would expect a result of 5 !!
a= 'word1 word2 word3'
a.rfind(' ',7)
11
Is this a bug ?
No. Don't you think someone would have found such an obvious bug by now?
if it's not a bug,
then the start index has no meaning ...
... and some would call that a bug.
Ah, I neglected to take your use of .rfind()'s second parameter into account!
As can be interpolated from the part of the docs James quotes:
s.rfind(' ', 7) === s[7:].rfind(' ') + 7 # overlooking the 'not present' case
That is, the second parameter to .rfind(), namely `start`, is relative
to the *left* end of the string, not the right end. I can see how this
might be unintuitive, but it does make the API more uniform.
It seems that the OP also thought it was relative to the left end of the string.
The difference is what it signifies: start of search, or end of search.
With rfind the "start" parameter signifies the end of the search, and
conversely, the third parameter "end" signifies where the search starts. :-)
Cheers,
- Alf
--
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Re: shove does not store data as expected
On Wed, Apr 21, 2010 at 2:51 AM, Alex wrote:
> I'm trying to use the shove module (http://pypi.python.org/pypi/shove)
> for a simple script. The script read a CSV file ad store the data.
> When I check the content of the "store" object (instance of Shove)
> *before* I close it, the data are all there but when I close and re-
> open it some data are lost. How it is possible? There is something
> wrong in my code or I didn't understand how shove works?
>
> Thanks in advance.
>
> Here is a sample of my code:
>
> DBNAME = "file://store.db"
>
> csv_file ="test.csv"
> cities = csv.reader(open(csv_file), delimiter=";")
> store = Shove(DBNAME, compress=True)
> for city,region,code in cities:
> entry_list = store.setdefault(region, [])
> data = 'just a sample'
> entry = {city:data}
> entry_list.append(entry)
If `shove` is like the std lib `shelve` module, the following might
fix the problem:
#untested
for city,region,code in cities:
entry_list = store.get(region, [])
data = 'just a sample'
entry = {city:data}
entry_list.append(entry)
store[region] = entry_list
Explanation:
The explicit assignment back to the `store` pseudo-dictionary lets it
properly update its internal state to reflect the change to the value
(in this case, the list) associated with the region key. In your
original version, you merely modified the list in-place, and (due to
the way Python works) `store` has no way of knowing that you've done
that and thus doesn't do the necessary bookkeeping, hence the behavior
you're observing.
See also: http://docs.python.org/library/shelve.html#example
And further note that shove seems to be beta and (apart from
docstrings in the source code) undocumented.
Cheers,
Chris
--
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Declarative programming for the Model part of an application
Dear all, Last week, I raised the question "Could declarative programming be useful for the Model part of an application ?", and I suggested an open-source project, Yoopf, to provide such a paradigm in Python. Stefan told me that the proposal lacked clarity. I have thus updated the description, and he now finds it much clearer. You can find it at http://www.yoopf.org So, I would appreciate your feedback again on such a project : can declarative programming be useful for the Model part of an application ? Do you think that Yoopf and its "programming by formula" paradigm can bring value to python developments ? How would it compare to database triggers and stored procedures, for example ? What could be some typical applications ? Many thanks in advance ! Pierre C. -- http://mail.python.org/mailman/listinfo/python-list
Tkinter question
Apologies in advance if this is a totally stupid question, I've tried looking at the Tkinter documentation on the web but since I'm something of an ignoramus when it comes to programming generally I didn't understand what I was reading. Anyway... I've written a module that allows me to manipulate sound data, and I've been trying to add a method to my sound class that shows me what a waveform looks like while I'm working on it in IDLE. After reading a bit about Tkinter, and via some trial and error, I came up with something a bit like this: def draw(self, w, h): out = Tkinter.Canvas(width = w, height = h) # a load of out.create_line(...)'s go here out.pack() out.mainloop() It works, but the problem is that I can't do anything else with IDLE until I close the image window. Is there a way around this, so that I can leave the image open while I continue to do other stuff? -- http://mail.python.org/mailman/listinfo/python-list
Re: error when printing a UTF-8 string (python 2.6.2)
Thanks for your insights. I have taken the easy way out, I read on a page that python 3 worked by default in UTF-8, so I downloaded and installed it. Apart from a few surprises (print is not a funtion, and rules about mixing spaces and tabs in indentation are much more strict, and I guess more is to come :^) everything now works transparently. Thanks again. -- Fabrice DELENTE -- http://mail.python.org/mailman/listinfo/python-list
Re: rfind bug ?
On 21-04-2010 12:33, Alf P. Steinbach wrote:
> * Chris Rebert:
>> On Wed, Apr 21, 2010 at 2:59 AM, Stef Mientki
>> wrote:
>>> On 21-04-2010 10:56, Chris Rebert wrote:
On Wed, Apr 21, 2010 at 1:51 AM, Stef Mientki
wrote:
> With the following code, I would expect a result of 5 !!
>
a= 'word1 word2 word3'
a.rfind(' ',7)
> 11
>
> Is this a bug ?
>
No. Don't you think someone would have found such an obvious bug by
now?
>>> if it's not a bug,
>>> then the start index has no meaning ...
>>> ... and some would call that a bug.
>>
>> Ah, I neglected to take your use of .rfind()'s second parameter into
>> account!
>>
>> As can be interpolated from the part of the docs James quotes:
>> s.rfind(' ', 7) === s[7:].rfind(' ') + 7 # overlooking the 'not
>> present' case
>>
>> That is, the second parameter to .rfind(), namely `start`, is relative
>> to the *left* end of the string, not the right end. I can see how this
>> might be unintuitive, but it does make the API more uniform.
>
> It seems that the OP also thought it was relative to the left end of
> the string.
>
> The difference is what it signifies: start of search, or end of search.
>
> With rfind the "start" parameter signifies the end of the search, and
> conversely, the third parameter "end" signifies where the search
> starts. :-)
>
thanks Alf,
that's indeed what I was missing.
cheers,
Stef
>
> Cheers,
>
> - Alf
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Re: rfind bug ?
On Wed, Apr 21, 2010 at 3:33 AM, Alf P. Steinbach wrote:
> * Chris Rebert:
>> On Wed, Apr 21, 2010 at 2:59 AM, Stef Mientki
>> wrote:
>>> On 21-04-2010 10:56, Chris Rebert wrote:
On Wed, Apr 21, 2010 at 1:51 AM, Stef Mientki
wrote:
>
> With the following code, I would expect a result of 5 !!
>
a= 'word1 word2 word3'
a.rfind(' ',7)
> 11
>
> Is this a bug ?
>
No. Don't you think someone would have found such an obvious bug by now?
>>> if it's not a bug,
>>> then the start index has no meaning ...
>>> ... and some would call that a bug.
>>
>> Ah, I neglected to take your use of .rfind()'s second parameter into
>> account!
>>
>> As can be interpolated from the part of the docs James quotes:
>> s.rfind(' ', 7) === s[7:].rfind(' ') + 7 # overlooking the 'not present'
>> case
>>
>> That is, the second parameter to .rfind(), namely `start`, is relative
>> to the *left* end of the string, not the right end. I can see how this
>> might be unintuitive, but it does make the API more uniform.
>
> It seems that the OP also thought it was relative to the left end of the
> string.
It really doesn't help that the example in question is kinda lousy
(particularly, it's symmetrical with respect to whitespace and has
only 2 spaces).
Case in point, my misinterpretation of the OP's misinterpretation
(i.e. having the indexing of `start` be relative to the end of the
string) still plausibly explains his confusion.
Cheers,
Chris
--
Excellent catch.
*Considers getting Alien Life-Form merch*
> The difference is what it signifies: start of search, or end of search.
>
> With rfind the "start" parameter signifies the end of the search, and
> conversely, the third parameter "end" signifies where the search starts. :-)
--
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Re: Tkinter question
On Wed, Apr 21, 2010 at 8:45 PM, Rotwang wrote: > def draw(self, w, h): > out = Tkinter.Canvas(width = w, height = h) > # a load of out.create_line(...)'s go here > out.pack() > out.mainloop() > > It works, but the problem is that I can't do anything else with IDLE until I > close the image window. Is there a way around this, so that I can leave the > image open while I continue to do other stuff? From reading the documentation myself (pydoc)... It would seem your only option is to make a thread out of this (not my preferred way - I was hoping it was possible to poll the Tk event system...). cheers James -- http://mail.python.org/mailman/listinfo/python-list
Re: Re: Code redundancy
Andreas Löscher wrote:
You can do something like this:
class A(): pass
inst=)
exec("""
... a=
... b=2
... c=3
... d=4
... """) in inst.__dict__
inst.a
1
This executes the Statement in the exec function and uses inst.__dict__
as namespace. But be aware, that this is not recommended. If you mess
with __dict__, you won't be able to replace it with some logic
(parameter) if you need to do something more than setting a variable.
Best
Hi Andreas, thanks for the reply,
Looks like I'll be sticking with repeating the class-name for a while.
Regards,
Alan
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Re: Japanese (speaking) developer needed for a bit of regex magic
Sebastian writes: > My regular expressions turn the Amazon error messages into Python > exceptions. > > This works fine as long as they are in English: "??? is not a valid > value for BrowseNodeId. Please change this value and retry your > request.", for instance, will raise an InvalidParameterValue > exception. However, the Japanese version returns the error message > "??? は、BrowseNodeIdの値として無効です。値を変更してから、再度リクエス > トを実行してください。" which will not be successfully handled. > > This renders the my module pretty much useless for Japanese users. Your problem, then, appears to be that you're attacking the issue at the wrong layer. Parsing messages in natural language and hoping to reconstruct a structure is going to be an exercise in frustration. Doesn't the API have defined response codes and parameters that you can use, instead of parsing error strings in various natural languages? -- \ “Giving every man a vote has no more made men wise and free | `\ than Christianity has made them good.” —Henry L. Mencken | _o__) | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: error when printing a UTF-8 string (python 2.6.2)
f...@slick.airforce-one.org wrote: > I have taken the easy way out, I read on a page that python 3 worked > by default in UTF-8, so I downloaded and installed it. Just a quick reminder: UTF-8 is not the same as unicode. Python3 works in unicode and by default uses UTF-8 to read from or write into files. Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: shove does not store data as expected
On 21 Apr, 12:36, Chris Rebert wrote: [cut] > > Explanation: > The explicit assignment back to the `store` pseudo-dictionary lets it > properly update its internal state to reflect the change to the value > (in this case, the list) associated with the region key. In your > original version, you merely modified the list in-place, and (due to > the way Python works) `store` has no way of knowing that you've done > that and thus doesn't do the necessary bookkeeping, hence the behavior > you're observing. > > See also:http://docs.python.org/library/shelve.html#example > > And further note that shove seems to be beta and (apart from > docstrings in the source code) undocumented. Thanks a lot for the clear explanation. It works! I will read the docs more carefully next time :-) Alex -- http://mail.python.org/mailman/listinfo/python-list
Re: Japanese (speaking) developer needed for a bit of regex magic
> > My regular expressions turn the Amazon error messages into Python > > exceptions. > > > This works fine as long as they are in English: "??? is not a valid > > value for BrowseNodeId. Please change this value and retry your > > request.", for instance, will raise an InvalidParameterValue > > exception. However, the Japanese version returns the error message > > "??? は、BrowseNodeIdの値として無効です。値を変更してから、再度リクエス > > トを実行してください。" which will not be successfully handled. > > > This renders the my module pretty much useless for Japanese users. > > Your problem, then, appears to be that you're attacking the issue at the > wrong layer. Parsing messages in natural language and hoping to > reconstruct a structure is going to be an exercise in frustration. > > Doesn't the API have defined response codes and parameters that you can > use, instead of parsing error strings in various natural languages? No, unfortunately not. If it did, I would have used it. The Amazon API returns an XML response which contains error messages if a request fails. These messages consist of an error code and an error description in natural language. Luckily, the description seems to stick to the same format and is (in all but one case) in plain English. Much to my dismay I discovered that the Japanese locale translates the error message! For example, this is the bit of XML returned for the German locale: AWS.InvalidParameterValue ??? is not a valid value for BrowseNodeId. Please change this value and retry your request. The corresponding part from the Japanese locale looks like this: AWS.InvalidParameterValue ??? は、BrowseNodeIdの値として無効です。値を変更してから、再度リクエストを実行してください。 Of course, one could argue that the type of error (in this case "AWS.InvalidParameterValue") would be enough. However, in order to return a maeningful error message, I would like to parse the description itself - and for this some knowledge of Japanese would be helpful. -- http://mail.python.org/mailman/listinfo/python-list
Re: Japanese (speaking) developer needed for a bit of regex magic
On Wed, Apr 21, 2010 at 4:46 AM, Sebastian wrote: >> > My regular expressions turn the Amazon error messages into Python >> > exceptions. >> >> > This works fine as long as they are in English: "??? is not a valid >> > value for BrowseNodeId. Please change this value and retry your >> > request.", for instance, will raise an InvalidParameterValue >> > exception. However, the Japanese version returns the error message >> > "??? は、BrowseNodeIdの値として無効です。値を変更してから、再度リクエス >> > トを実行してください。" which will not be successfully handled. >> >> > This renders the my module pretty much useless for Japanese users. >> >> Your problem, then, appears to be that you're attacking the issue at the >> wrong layer. Parsing messages in natural language and hoping to >> reconstruct a structure is going to be an exercise in frustration. >> >> Doesn't the API have defined response codes and parameters that you can >> use, instead of parsing error strings in various natural languages? > > No, unfortunately not. If it did, I would have used it. > > The Amazon API returns an XML response which contains error messages > if a request fails. These messages consist of an error code and an > error description in natural language. Luckily, the description seems > to stick to the same format and is (in all but one case) in plain > English. Much to my dismay I discovered that the Japanese locale > translates the error message! > > For example, this is the bit of XML returned for the German locale: > > > > AWS.InvalidParameterValue > ??? is not a valid value for BrowseNodeId. Please > change this value and retry your request. > > > > The corresponding part from the Japanese locale looks like this: > > > > AWS.InvalidParameterValue > ??? > は、BrowseNodeIdの値として無効です。値を変更してから、再度リクエストを実行してください。 Message> > > > > Of course, one could argue that the type of error (in this case > "AWS.InvalidParameterValue") would be enough. However, in order to > return a maeningful error message, I would like to parse the > description itself - and for this some knowledge of Japanese would be > helpful. Just throwing this out there, but perhaps you could grep for the relevant terms in the error message and intuit it from there? For example: # terms = whatever the actual param names are terms = "BrowseNodeId FooNodeId FooQueryType".split() for term in terms: if term in err_msg: raise AmazonError, err_code + " for " +repr(term) Cheers, Chris -- http://blog.rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
socked and bytes operation
Hello i have this question :
i connect to the server in this way:
sock = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
sock.connect(('192.168.1.11',11502))
rcv = sock.recv(8124)
here i get 14 random bytes , in a string with strange chars like :
¬¨^.á‹•Ò
a„ãj
I think because sock.recv return a string.
Now i have to xor this 14 bytes with a key stored in file as a sting.
Can you help me to understand how to do it.
Thanks
Luca
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Inline Calculation of Dictionary Values
Hi,
Is it possible to something along these lines in python :-
map = {
'key1': f(),
'key2': modify_state(); val = f(); restore_state(); val,
'key3': f(),
}
For 'key2' I want to store the value returned by f() but after
modifying the state. Do we have something like a "bare block". I am
trying to avoid this :-
def f2():
modify_state()
val = f()
restore_state()
return val
map = {
'key1': f(),
'key2': f2()
'key3': f(),
}
Thank You,
Himanshu
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Re: socked and bytes operation
On Wed, Apr 21, 2010 at 5:37 AM, luca72 wrote:
> Hello i have this question :
> i connect to the server in this way:
> sock = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
> sock.connect(('192.168.1.11',11502))
> rcv = sock.recv(8124)
> here i get 14 random bytes , in a string with strange chars like :
> ¬¨^.á‹•Ò
> a„ãj
> I think because sock.recv return a string.
> Now i have to xor this 14 bytes with a key stored in file as a sting.
> Can you help me to understand how to do it.
# Disclaimer: Completely untested
from itertools import cycle
f = open("path/to/key_file", 'r') # open file
key = f.read() # read from file
f.close() # close file
# convert strings to lists of integers
rcv = map(ord, rcv)
key = map(ord, key)
plain_chars = []
# do the XOR-ing
for cypher_char, key_char in zip(rcv, cycle(key)):
plain_char = chr(ord(cypher_char) ^ ord(key_char))
plain_chars.append(plain_char)
# join decrypted characters into a string
# and output it
print ''.join(plain_chars) # Python idiom
You'll probably need to read up on what zip(), map(), ord(), and chr() do:
http://docs.python.org/library/functions.html
Cheers,
Chris
--
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Re: error when printing a UTF-8 string (python 2.6.2)
Hi Peter, > Just a quick reminder: UTF-8 is not the same as unicode. Python3 works in > unicode and by default uses UTF-8 to read from or write into files. I'm not the OP, but wanted to make sure I was fully understanding your point. Are you saying all open() calls in Python that read text files, automatically convert UTF-8 content to Unicode in the same manner as the following might when using Python 2.6? codecs.open( fileName, mode='r', encoding='UTF8', ... ) Thanks for your feedback, Malcolm -- http://mail.python.org/mailman/listinfo/python-list
Re: Inline Calculation of Dictionary Values
On Wed, Apr 21, 2010 at 5:51 AM, ++imanshu wrote:
> Is it possible to something along these lines in python :-
>
> map = {
> 'key1': f(),
> 'key2': modify_state(); val = f(); restore_state(); val,
> 'key3': f(),
> }
>
> For 'key2' I want to store the value returned by f() but after
> modifying the state. Do we have something like a "bare block".
Based on what I can find about "bare blocks", Nope. And we like it that way :-)
> I am
> trying to avoid this :-
>
> def f2():
> modify_state()
> val = f()
> restore_state()
> return val
>
> map = {
> 'key1': f(),
> 'key2': f2()
> 'key3': f(),
> }
FWIW, I don't see what's wrong with this. You could probably refactor
f2() to use the `with` statement and a context manager, but that's
getting tangential.
However, the question arises: Why do you have global state in the first place?
Cheers,
Chris
--
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Re: Write web apps in Python?
Bruno Desthuilliers wrote: > Nope. I want to keep all my settings parsed, my librairies loaded, all > my connections opened etc. That is, all the time consuming stuff at app > startup - which, with PHP, mostly happens for each and every request. O.K. I wasn't clear on your objection. As I said the first time, I think you've gotten some bad info on PHP. Or maybe you're just behind the times. > Many large, sopĥisticated etc applications are written in C. Does that > make C a practical application programming language ? It's at least a strong clue. > Now I'm sorry to say that for quite a few "sophisticated" PHP apps I've > seen (and eventually had to work on), the "startup" part - parsing the > include files, configuration, establishing connections etc - took a good > part of the total processing time. You didn't say when that was, but PHP caching has come a long way. Google is your friend. -- --Bryan -- http://mail.python.org/mailman/listinfo/python-list
Re: error when printing a UTF-8 string (python 2.6.2)
pyt...@bdurham.com wrote: > Are you saying all open() calls in Python that read text files, > automatically convert UTF-8 content to Unicode in the same manner as the > following might when using Python 2.6? > > codecs.open( fileName, mode='r', encoding='UTF8', ... ) That's what I meant to say, but it's not actually true. Quoting http://docs.python.org/py3k/library/functions.html#open """ open(file, mode='r', buffering=None, encoding=None, errors=None, newline=None, closefd=True) [...] encoding is the name of the encoding used to decode or encode the file. This should only be used in text mode. The default encoding is platform dependent (whatever locale.getpreferredencoding() returns), but any encoding supported by Python can be used. See the codecs module for the list of supported encodings. """ So it just happend to be UTF-8 on my machine. Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: python glibc crypt() function
On Wed, Apr 21, 2010 at 2:29 AM, luca72 wrote: > On 20 Apr, 19:38, Peter Otten <__pete...@web.de> wrote: >> luca72 wrote: >> > Hello i have to do this : >> > glibc crypt() function, using salt $1$abcdefgh$ >> >> > cryptPw = crypt(plainPw, "$1$abcdefgh$") > Thanks > The result is correct i obtain the same with ctypes and crypt module, > so i think that is better to use the crypt module is correct? > > Luca Be aware that the beginning of the salt string determines the type of hash you're using, and it looks to me like that's the old-style MD5-based hash. It's far from 'broken', but it has a few issues. Better would be to move to the SHA512-based $6$ if your platform supports it. Geremy Condra -- http://mail.python.org/mailman/listinfo/python-list
Re: Write web apps in Python?
Bryan a écrit : Bruno Desthuilliers wrote: Nope. I want to keep all my settings parsed, my librairies loaded, all my connections opened etc. That is, all the time consuming stuff at app startup - which, with PHP, mostly happens for each and every request. O.K. I wasn't clear on your objection. As I said the first time, I think you've gotten some bad info on PHP. Well, I have to admit I've only used it professionnaly for the past 6 years or so, so my knowledge may be a bit lacking... Many large, sopĥisticated etc applications are written in C. Does that make C a practical application programming language ? It's at least a strong clue. Oh, yes ? Then why don't you use C for web programming ?-) -- http://mail.python.org/mailman/listinfo/python-list
Re: error when printing a UTF-8 string (python 2.6.2)
Hi Peter, >> Are you saying all open() calls in Python that read text files, >> automatically convert UTF-8 content to Unicode in the same manner as the >> following might when using Python 2.6? >> >> codecs.open( fileName, mode='r', encoding='UTF8', ... ) > That's what I meant to say, but it's not actually true. Thanks for the clarification. It sounds like Python 3 has unified the standard library open() function and the codecs.open() into a single function? In other words, would it be accurate to say that in Python 3, there is no longer a need to use codecs.open()? Any idea if the above applies to Python 2.7? Thank you Peter! Malcolm -- http://mail.python.org/mailman/listinfo/python-list
Re: Inline Calculation of Dictionary Values
++imanshu wrote:
Hi,
Is it possible to something along these lines in python :-
map = {
'key1': f(),
'key2': modify_state(); val = f(); restore_state(); val,
'key3': f(),
}
For 'key2' I want to store the value returned by f() but after
modifying the state. Do we have something like a "bare block". I am
trying to avoid this :-
def f2():
modify_state()
val = f()
restore_state()
return val
map = {
'key1': f(),
'key2': f2()
'key3': f(),
}
Thank You,
Himanshu
How about something like:
mymap = {
'key1': f(),
'key2': [modify_state(), f(), restore_state()][1],
'key3': f(),
}
This builds a list of three values, and uses only the [1] item from the
list.
DaveA
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Re: Write web apps in Python?
On 04/21/2010 08:46 AM, Bruno Desthuilliers wrote: Bryan a écrit : Bruno Desthuilliers wrote: Many large, sopĥisticated etc applications are written in C. Does that make C a practical application programming language ? It's at least a strong clue. Oh, yes ? Then why don't you use C for web programming ?-) Many large, sophisticated etc applications are written in COBOL too. I'm sure it makes a practical web programming language too... ;-) -tkc -- http://mail.python.org/mailman/listinfo/python-list
Re: Inline Calculation of Dictionary Values
On Apr 21, 7:31 pm, Dave Angel wrote:
> ++imanshu wrote:
> > Hi,
>
> > Is it possible to something along these lines in python :-
>
> > map = {
> > 'key1': f(),
> > 'key2': modify_state(); val = f(); restore_state(); val,
> > 'key3': f(),
> > }
>
> > For 'key2' I want to store the value returned by f() but after
> > modifying the state. Do we have something like a "bare block". I am
> > trying to avoid this :-
>
> > def f2():
> > modify_state()
> > val = f()
> > restore_state()
> > return val
>
> > map = {
> > 'key1': f(),
> > 'key2': f2()
> > 'key3': f(),
> > }
>
> > Thank You,
> > Himanshu
>
> How about something like:
>
> mymap = {
> 'key1': f(),
> 'key2': [modify_state(), f(), restore_state()][1],
> 'key3': f(),
>
> }
>
> This builds a list of three values, and uses only the [1] item from the
> list.
>
> DaveA
This is cool. I'll use it.
Thank You,
Himanshu
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Re: Inline Calculation of Dictionary Values
On Apr 21, 6:10 pm, Chris Rebert wrote:
> On Wed, Apr 21, 2010 at 5:51 AM, ++imanshu wrote:
> > Is it possible to something along these lines in python :-
>
> > map = {
> > 'key1': f(),
> > 'key2': modify_state(); val = f(); restore_state(); val,
> > 'key3': f(),
> > }
>
> > For 'key2' I want to store the value returned by f() but after
> > modifying the state. Do we have something like a "bare block".
>
> Based on what I can find about "bare blocks", Nope. And we like it that way
> :-)
>
> > I am
> > trying to avoid this :-
>
> > def f2():
> > modify_state()
> > val = f()
> > restore_state()
> > return val
>
> > map = {
> > 'key1': f(),
> > 'key2': f2()
> > 'key3': f(),
> > }
>
> FWIW, I don't see what's wrong with this. You could probably refactor
> f2() to use the `with` statement and a context manager, but that's
> getting tangential.
> However, the question arises: Why do you have global state in the first place?
>
> Cheers,
> Chris
> --http://blog.rebertia.com
f() = flavor independent os api for getting path to a folder, uses
effective user id (eg Folder.FSFindFolder(Folders.kUserDomain,
Folders.kInternetPlugInFolderType, Folders.kDontCreateFolder))
modify_state() = change current effective user id
restore_state() = restore to old user id
Thanks for the reply.
Thank You,
Himanshu
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Re: Tkinter question
On Apr 21, 12:45 pm, Rotwang wrote: > Apologies in advance if this is a totally stupid question, I've tried > looking at the Tkinter documentation on the web but since I'm something > of an ignoramus when it comes to programming generally I didn't > understand what I was reading. Anyway... > > I've written a module that allows me to manipulate sound data, and I've > been trying to add a method to my sound class that shows me what a > waveform looks like while I'm working on it in IDLE. After reading a bit > about Tkinter, and via some trial and error, I came up with something a > bit like this: > > def draw(self, w, h): > out = Tkinter.Canvas(width = w, height = h) > # a load of out.create_line(...)'s go here > out.pack() > out.mainloop() > > It works, but the problem is that I can't do anything else with IDLE > until I close the image window. Is there a way around this, so that I > can leave the image open while I continue to do other stuff? Just run your program directly, either from a terminal or a DOS console or by double-clicking on it in a file manager if the proper file associations have been defined (they are by default on Windows). There might be some IDLE trick to make it work, but I don't use IDLE myself. HTH - Eric - -- http://mail.python.org/mailman/listinfo/python-list
Re: Inline Calculation of Dictionary Values
Dave Angel wrote:
> ++imanshu wrote:
>> Hi,
>>
>> Is it possible to something along these lines in python :-
>>
>> map = {
>> 'key1': f(),
>> 'key2': modify_state(); val = f(); restore_state(); val,
>> 'key3': f(),
>> }
>>
>> For 'key2' I want to store the value returned by f() but after
>> modifying the state. Do we have something like a "bare block". I am
>> trying to avoid this :-
>>
>> def f2():
>> modify_state()
>> val = f()
>> restore_state()
>> return val
>>
>> map = {
>> 'key1': f(),
>> 'key2': f2()
>> 'key3': f(),
>> }
>>
>> Thank You,
>> Himanshu
>>
>>
> How about something like:
>
> mymap = {
> 'key1': f(),
> 'key2': [modify_state(), f(), restore_state()][1],
> 'key3': f(),
> }
>
> This builds a list of three values, and uses only the [1] item from the
> list.
Please think of the children ;)
The function based approach is the way to go:
def f2():
cookie = modify_state()
try:
return f()
finally:
restore_state(cookie)
This will restore the state even if f() raises an exception.
If you want something more fancy you can parameterize f2() by the three
functions or look into context managers.
Peter
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Re: Japanese (speaking) developer needed for a bit of regex magic
On 4/21/2010 7:46 AM, Sebastian wrote: The Amazon API returns an XML response which contains error messages if a request fails. These messages consist of an error code and an error description in natural language. Luckily, the description seems to stick to the same format and is (in all but one case) in plain English. Much to my dismay I discovered that the Japanese locale translates the error message! Could you, when you get an error message, resubmit the request in the standard locale so you get the messages in English? Or is the 'locale' set by the url -- amazon.com versus amazon.co.jp? After you parse, are you trying to formulate a substitute message in Japanese? Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
Re: Japanese (speaking) developer needed for a bit of regex magic
On 4/21/2010 5:31 AM, Sebastian wrote: This works fine as long as they are in English: "??? is not a valid value for BrowseNodeId. > Please change this value and retry your request.", > for instance, will raise an InvalidParameterValue exception. However, the Japanese version returns the error message "??? は、BrowseNodeIdの値として無効です。値を変更してから、再度リクエストを実行してください。" My daughter, in 2nd year college Japanese, says that the above is basically a translation of the English boilerplate. The only variable info is 'BrowserNodeId', which you can read just fine already. So we do not understand what your problem is and what you want to accomplish. I have a collection of sample messages here (all files *-jp-*.xml): http://bitbucket.org/basti/python-amazon-product-api/src/tip/tests/2009-11-01/ Is this a commercial product? Are you willing to pay for serious help, if needed? Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
Re: error when printing a UTF-8 string (python 2.6.2)
On 4/21/2010 9:29 AM, Peter Otten wrote: pyt...@bdurham.com wrote: Are you saying all open() calls in Python that read text files, automatically convert UTF-8 content to Unicode in the same manner as the following might when using Python 2.6? codecs.open( fileName, mode='r', encoding='UTF8', ... ) That's what I meant to say, but it's not actually true. I wish it were, though. Quoting http://docs.python.org/py3k/library/functions.html#open """ open(file, mode='r', buffering=None, encoding=None, errors=None, newline=None, closefd=True) [...] encoding is the name of the encoding used to decode or encode the file. This should only be used in text mode. The default encoding is platform dependent (whatever locale.getpreferredencoding() returns), but any encoding supported by Python can be used. See the codecs module for the list of supported encodings. """ So it just happend to be UTF-8 on my machine. Unfortunately, it is not on US Windows. Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
xml.dom.minidom character encoding
I have the following simple script running on 2.5.2 on a machine where the default character encoding is "ascii": #!/usr/bin/env python #coding: utf-8 import xml.dom.minidom import codecs str=u"" doc=xml.dom.minidom.parseString( str ) xml=doc.toxml( encoding="utf-8" ) file=codecs.open( "foo.xml", "w", "utf-8" ) file.write( xml ) file.close() I've specified utf-8 every place I can find that the documentation allows me to, and yet this doesn't even come close to working without UnicodeEncodeErrors. What on Earth do I have to do to please the character encoding gods? -- http://mail.python.org/mailman/listinfo/python-list
Re: xml.dom.minidom character encoding
C. Benson Manica wrote:
> I have the following simple script running on 2.5.2 on a machine where
> the default character encoding is "ascii":
>
> #!/usr/bin/env python
> #coding: utf-8
>
> import xml.dom.minidom
> import codecs
>
> str=u" \"ó\"/>"
> doc=xml.dom.minidom.parseString( str )
> xml=doc.toxml( encoding="utf-8" )
> file=codecs.open( "foo.xml", "w", "utf-8" )
> file.write( xml )
> file.close()
>
> I've specified utf-8 every place I can find that the documentation
> allows me to, and yet this doesn't even come close to working without
> UnicodeEncodeErrors. What on Earth do I have to do to please the
> character encoding gods?
Verify every step as you proceed?
>>> import xml.dom.minidom
>>> s = u""
>>> doc = xml.dom.minidom.parseString(s)
Traceback (most recent call last):
File "", line 1, in
File "/usr/lib/python2.5/xml/dom/minidom.py", line 1925, in parseString
return expatbuilder.parseString(string)
File "/usr/lib/python2.5/xml/dom/expatbuilder.py", line 940, in
parseString
return builder.parseString(string)
File "/usr/lib/python2.5/xml/dom/expatbuilder.py", line 223, in
parseString
parser.Parse(string, True)
UnicodeEncodeError: 'ascii' codec can't encode character u'\xf3' in position
62: ordinal not in range(128)
It seems that parseString() doesn't like unicode -- let's try a byte string
then:
>>> doc = xml.dom.minidom.parseString(s.encode("utf-8"))
>>> xml = doc.toxml(encoding="utf-8")
No complaints -- let's have a look at the result:
>>> xml
''
That's a byte string, no need for codecs.open() then:
>>> f = open("foo.xml", "w")
>>> f.write(xml)
>>> f.close()
Peter
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Re: xml.dom.minidom character encoding
On Apr 21, 1:58 pm, Peter Otten <__pete...@web.de> wrote:
> C. Benson Manica wrote:
>> (snip)
>
> It seems that parseString() doesn't like unicode
Yes, I noticed that, and I already tried...
> -- let's try a byte string
> then:
>
> >>> doc = xml.dom.minidom.parseString(s.encode("utf-8"))
> >>> xml = doc.toxml(encoding="utf-8")
...except that it didn't work:
File "./demo.py", line 8, in
doc=xml.dom.minidom.parseString( str.encode("utf-8") )
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position
62: ordinal not in range(128)
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Re: socked and bytes operation
luca72 wrote:
Hello i have this question :
i connect to the server in this way:
sock = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
sock.connect(('192.168.1.11',11502))
rcv = sock.recv(8124)
here i get 14 random bytes , in a string with strange chars like :
¬¨^.á‹•Ò
a„ãj
I think because sock.recv return a string.
Now i have to xor this 14 bytes with a key stored in file as a sting.
Can you help me to understand how to do it.
Port 11502? What are you talking to? An eSoft Distributed
Intelligent Architecture node? Unlikely. Let me guess. A Counter-Strike
server.
John Nagle
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Re: xml.dom.minidom character encoding
C. Benson Manica wrote:
> On Apr 21, 1:58 pm, Peter Otten <__pete...@web.de> wrote:
>> C. Benson Manica wrote:
>>> (snip)
>>
>> It seems that parseString() doesn't like unicode
>
> Yes, I noticed that, and I already tried...
>
>> -- let's try a byte string
>> then:
>>
>> >>> doc = xml.dom.minidom.parseString(s.encode("utf-8"))
>> >>> xml = doc.toxml(encoding="utf-8")
>
> ...except that it didn't work:
>
> File "./demo.py", line 8, in
> doc=xml.dom.minidom.parseString( str.encode("utf-8") )
> UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position
> 62: ordinal not in range(128)
Are you sure that your script has
str = u"..."
like in your post and not just
str = "..."
?
Peter
--
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Re: Write web apps in Python?
Bruno Desthuilliers wrote: > Bryan a écrit : > > > Bruno Desthuilliers wrote: > >> Nope. I want to keep all my settings parsed, my librairies loaded, all > >> my connections opened etc. That is, all the time consuming stuff at app > >> startup - which, with PHP, mostly happens for each and every request. > > > O.K. I wasn't clear on your objection. As I said the first time, I > > think you've gotten some bad info on PHP. > > Well, I have to admit I've only used it professionnaly for the past 6 > years or so, so my knowledge may be a bit lacking... Competent PHP developers know how to cache libraries and various connections and configurations. If that's been a stumbling point if your own work, well, again, Google is your friend. > >> Many large, sopĥisticated etc applications are written in C. Does that > >> make C a practical application programming language ? > > > It's at least a strong clue. > > Oh, yes ? Then why don't you use C for web programming ?-) Did you forget what you argued? Had you said that PHP is impractical for writing operating systems, I would have silently agreed. You wrote the howler: "The PHP execution model (mostly based on CGI FWIW) tends to be a bit unpractical for non-trivial applications". PHP *rocks* for serious web apps. PHP is specifically designed for web apps. PHP became a major-league programming language *soley* on its strength and success in building web apps. Popular as PHP is, it "tends to be a bit unpractical" for anything but web apps. 'Round here we love Python. I prefer Python to Perl or PHP even in those languages' particular areas of specialization. Advocating for Python does not require spreading myths about PHP. -- --Bryan -- http://mail.python.org/mailman/listinfo/python-list
Re: xml.dom.minidom character encoding
On Apr 21, 2:25 pm, Peter Otten <__pete...@web.de> wrote:
> Are you sure that your script has
>
> str = u"..."
>
> like in your post and not just
>
> str = "..."
No :-)
str=u""
doc=xml.dom.minidom.parseString( str.encode("utf-8") )
xml=doc.toxml( encoding="utf-8")
file=codecs.open( "foo.xml", "w", "utf-8" )
file.write( xml )
file.close()
fails:
File "./demo.py", line 12, in
file.write( xml )
File "/usr/lib/python2.5/codecs.py", line 638, in write
return self.writer.write(data)
File "/usr/lib/python2.5/codecs.py", line 303, in write
data, consumed = self.encode(object, self.errors)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position
62: ordinal not in range(128)
but dropping the encoding argument to doc.toxml() seems to finally
work. I'd be curious to know why the code you posted (that worked for
you) didn't for me, but at this point I'm just happy with something
functional. Thank you very kindly!
--
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Re: xml.dom.minidom character encoding
C. Benson Manica wrote:
> On Apr 21, 2:25 pm, Peter Otten <__pete...@web.de> wrote:
>
>> Are you sure that your script has
>>
>> str = u"..."
>>
>> like in your post and not just
>>
>> str = "..."
>
> No :-)
>
> str=u" \"ó\"/>"
> doc=xml.dom.minidom.parseString( str.encode("utf-8") )
> xml=doc.toxml( encoding="utf-8")
> file=codecs.open( "foo.xml", "w", "utf-8" )
> file.write( xml )
> file.close()
>
> fails:
>
> File "./demo.py", line 12, in
> file.write( xml )
> File "/usr/lib/python2.5/codecs.py", line 638, in write
> return self.writer.write(data)
> File "/usr/lib/python2.5/codecs.py", line 303, in write
> data, consumed = self.encode(object, self.errors)
> UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position
> 62: ordinal not in range(128)
But that's a different error (codecs.open().write()) on a different line.
What you said was failing (xml.dom.minidom.parseString()) worked.
> but dropping the encoding argument to doc.toxml() seems to finally
> work. I'd be curious to know why the code you posted (that worked for
> you) didn't for me, but at this point I'm just happy with something
> functional. Thank you very kindly!
The following worked for me an should work for you, too:
$ cat tmp.py
#!/usr/bin/env python
# -*- coding: utf-8 -*-
import xml.dom.minidom
str = u""
doc = xml.dom.minidom.parseString(str.encode("utf-8"))
xml = doc.toxml(encoding="utf-8")
file = open("foo.xml", "w")
file.write( xml )
file.close()
$ python2.5 tmp.py
$ cat foo.xml
$
Btw., str is a bad variable name because it shadows the builtin str type.
Peter
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Re: Write web apps in Python?
On 4/21/2010 11:37 AM Bryan said... 'Round here we love Python. I prefer Python to Perl or PHP even in those languages' particular areas of specialization. Advocating for Python does not require spreading myths about PHP. You're missing the point -- set-up and tear-down overhead is involved for both python and php cgi based web serving, and Bruno I'm sure would concur that python in this suffers similarly. You point at exactly the issue when you noted earlier: Bryan> I think I see what you mean -- correct me if Bryan> I'm wrong: You want to keep complex application Bryan> data structures around between requests. That Bryan> sounds appealing in terms of efficiency, but Bryan> it's bad for scalability and robustness. It's more than appealing -- for example, it's fact with Zope, where Zeo adds the scalability. Emile -- http://mail.python.org/mailman/listinfo/python-list
Re: Usable street address parser in Python?
In article <4bcddc5a$0$1630$742ec...@news.sonic.net>, John Nagle wrote: >Iain King wrote: >> Not sure on the volume of addresses you're working with, but as an >> alternative you could try grabbing the zip code, looking up all >> addresses in that zip code, and then finding whatever one of those >> address strings most closely resembles your address string (smallest >> Levenshtein distance?). > >The parser doesn't have to be perfect, but it should >reliably reports when it fails. Then I can run the hard cases through >one of the commercial online address standardizers. I'd like to >be able to knock off the easy cases cheaply. In a similar situation I did the exact reverse. ( analysing assembler code sequences for the stack effect.) I made a list of all exceptions, and checked against that first. If it is not an exception, the rule should apply. If it doesn't, call Houston. (Of course one starts with making an input canonical, all upper case maybe reordering etc.) > >What I want to do is to first extract the street number and >undecorated street name only, match that to a large database of US businesses >stored in MySQL, and then find the best match from the database >hits. So I need reliable extraction of undecorated street name and number. >The >other fields are less important. This kind of problem remains very tricky ... At least in the Netherlands we have a book containing information about how the spelling of a street should be officially using a limited number of characters. > > John Nagle Groetjes Albert -- -- Albert van der Horst, UTRECHT,THE NETHERLANDS Economic growth -- being exponential -- ultimately falters. alb...@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst -- http://mail.python.org/mailman/listinfo/python-list
ctypes errcheck question
According to the ctypes docs: http://docs.python.org/library/ctypes.html An errcheck function should return the args tuple when used with out parameters (section 15.15.2.4. Function prototypes). However, in other cases it says to return the result, or whatever result you want returned from the function. I have a single errcheck function that checks result codes and throws an exception if the result indicates an error. I'd like to reuse it with a number of different function, some of which are specified with out parameters, and some of which are specified in the normal method: func = my_lib.func func.restype = c_long func.argtypes = [c_int, etc] So, my question is can do I have my errcheck function return the args tuple in both cases? The documentation seems kind of ambiguous about how it will behave if a function loaded without output parameters returns the arguments tuple from errcheck. Thanks, Brendan -- http://mail.python.org/mailman/listinfo/python-list
Deleting more than one element from a list
Is the del instruction able to remove _at the same_ time more than one element from a list ? For instance, this seems to be correct : >>> z=[45,12,96,33,66,'c',20,99] >>> del z[2], z[6],z[0] >>> z [12, 33, 66, 'c', 20] >>> However, the following doesn't work : >> z=[45,12,96,33,66,'c',20,99] >>> del z[2], z[3],z[6] Traceback (most recent call last): File "", line 1, in IndexError: list assignment index out of range >>> Does it mean the instruction del z[2], z[3],z[6] to be equivalent to the successive calls del z[2] del z[3] del z[6] ? -- http://mail.python.org/mailman/listinfo/python-list
Re: Deleting more than one element from a list
On 21 April 2010 20:56, candide wrote: > Is the del instruction able to remove _at the same_ time more than one > element from a list ? Yup: >>> z=[45,12,96,33,66,'c',20,99] >>> del z[:] >>> z [] -- Cheers, Simon B. -- http://mail.python.org/mailman/listinfo/python-list
Re: Deleting more than one element from a list
candide wrote: Is the del instruction able to remove _at the same_ time more than one element from a list ? For instance, this seems to be correct : >>> z=[45,12,96,33,66,'c',20,99] >>> del z[2], z[6],z[0] >>> z [12, 33, 66, 'c', 20] >>> However, the following doesn't work : >> z=[45,12,96,33,66,'c',20,99] >>> del z[2], z[3],z[6] Traceback (most recent call last): File "", line 1, in IndexError: list assignment index out of range >>> Does it mean the instruction del z[2], z[3],z[6] to be equivalent to the successive calls del z[2] del z[3] del z[6] Yes, those are equivalent. The reason it fails is that, by the time it gets around to the third delete, there is no longer in index [6] in the list. The element you were thinking of is now at index [4]. This, however, will work as you expected: del z[6], z[3],z[2] -- Gary Herron, PhD. Department of Computer Science DigiPen Institute of Technology (425) 895-4418 -- http://mail.python.org/mailman/listinfo/python-list
Re: Deleting more than one element from a list
On Apr 21, 2:56 pm, candide wrote: > Is the del instruction able to remove _at the same_ time more than one > element from a list ? > > For instance, this seems to be correct : > > >>> z=[45,12,96,33,66,'c',20,99] > >>> del z[2], z[6],z[0] > >>> z > [12, 33, 66, 'c', 20] > >>> > > However, the following doesn't work : > > >> z=[45,12,96,33,66,'c',20,99] > >>> del z[2], z[3],z[6] > Traceback (most recent call last): > File "", line 1, in > IndexError: list assignment index out of range > >>> > > Does it mean the instruction > > del z[2], z[3],z[6] > > to be equivalent to the successive calls > > del z[2] > del z[3] > del z[6] That's part of the problem. Let's look at a better example. >>> z = [0,1,2,3,4,5,6] >>> del z[0],z[3],z[6] Traceback (most recent call last): File "", line 1, in del z[0],z[3],z[6] IndexError: list assignment index out of range >>> z [1, 2, 3, 5, 6] Yes, the error was caused by the list shrinking between calls, so the 6 did not get deleted. But notice that 3 is still there and 4 is missing. If you must delete this way, do it bottom up so that the index remains valid for the subsequent calls: >>> z = [0,1,2,3,4,5,6] >>> del z[6],z[3],z[0] >>> z [1, 2, 4, 5] > > ? -- http://mail.python.org/mailman/listinfo/python-list
Re: Deleting more than one element from a list
On 4/21/2010 12:56 PM candide said... Is the del instruction able to remove _at the same_ time more than one element from a list ? For instance, this seems to be correct : >>> z=[45,12,96,33,66,'c',20,99] Not as I see it -- watch your index values - they change after each delete is completed. It'll work if you order them backwards though. >>> a = range(10) >>> del a[0],a[2],a[4],a[6] >>> a [1, 2, 4, 5, 7, 8] >>> a = range(10) >>> del a[6],a[4],a[2],a[0] >>> a [1, 3, 5, 7, 8, 9] >>> Emile -- http://mail.python.org/mailman/listinfo/python-list
Windows debugging symbols for python 2.5.4 and pywin32 214
Hi everyone, I have a production server running a Windows Service written in Python, which uses python 2.5.4 (yes I know it is old, but I am somewhat stuck with this for now) and pywin32 214. Given a set of manipulations, I get a stack overflow in the service, and a bad crash. The same operation when running without win32serviceutil.ServiceFramework does not trigger the bug. I'm looking for some debugging tools (debug build of the interpreter and the pywin32 libraries) that some good soul could have kept from a previous debugging session to try to get a C stack trace and understand what causes this. Any hint towards what could cause that stack overflow would be welcome too. The application is multithreaded (and uses pyro and twisted). I can provide more information for the curious. Many thanks. -- Alexandre Fayolle Logilab, Paris, France. -- http://mail.python.org/mailman/listinfo/python-list
Looking for registration package
I'm looking for a Python-based, small, self-contained package to hand out API keys, in the same spirit as Google API keys. The basic specs are simple: 1) enforce the "one key per customer" rule; 2) be robot-proof; 3) be reasonably difficult to circumvent even for humans. (This is for a web service we would like to implement; the goal is to be able to control the load on our servers. Therefore, if the package includes an automated log-analysis component, all the better, but this is not necessary.) Any suggestions would be appreciated. Thanks! ~K -- http://mail.python.org/mailman/listinfo/python-list
ctypes: delay conversion from c_char_p to string
I have a function exposed through ctypes that returns a c_char_p. Since I need to deallocate that c_char_p, it's inconvenient that ctypes copies the c_char_p into a string instead of giving me the raw pointer. I believe this will cause a memory leak, unless ctypes is smart enough to free the string itself after the copy... which I doubt. Is there some way to tell ctypes to return an actual c_char_p, or is my best bet to return a c_void_p and cast to c_char_p when I'm reading to convert to a string? Thanks Brendan -- http://mail.python.org/mailman/listinfo/python-list
Python-URL! - weekly Python news and links (Mar 9)
QOTW: "I used to think anonymous functions (AKA blocks, etc...) would be a nice feature for Python. Then I looked at a stack trace from a different programming language with lots of anonymous functions. (I believe it was perl.) I became enlightened." - Jonathan Gardner, apparently echoing Guido's criterion of debuggability in language design http://groups.google.com/group/comp.lang.python/msg/3ebe7a0b78086acf Editor Cameron Laird apologizes for the following three entries, which appeared in the last installment only in an unusably garbled form: There is no module in the standard library to handle filesystem paths in an OO way - but why? http://groups.google.com/group/comp.lang.python/t/f580fb3763208425/ A "History Channel" special: how the way a TAB key was interpreted changed over time http://groups.google.com/group/comp.lang.python/t/82d9181fcd31ffe4/ After a false start, finally we get our first "Is it Call-By-Value or Call-By-Reference?" thread of the year! http://groups.google.com/group/comp.lang.python/t/fd36962c4970ac48/ --- Back in the present, Three new preliminary Python versions are now available for testing: Python 2.7 alpha 4 http://groups.google.com/group/comp.lang.python/t/779e761d934dbc1a/ Python 3.1.2 release candidate http://permalink.gmane.org/gmane.comp.python.general/656887 Python 2.6.5 release candidate 1 http://permalink.gmane.org/gmane.comp.python.devel/111319 Forget those Java recipes when implementing the Singleton pattern: http://groups.google.com/group/comp.lang.python/t/9228a3763eb552b3/ How to obtain a module docstring without actually importing it: http://groups.google.com/group/comp.lang.python/t/ca97d63ace6ea81d/ Do something only if a certain module is already in use by the current program: http://groups.google.com/group/comp.lang.python/t/ee22c223fa73a429/ Functions, bound methods, unbound ones: what are their differences? http://groups.google.com/group/comp.lang.python/t/72ab93ba395822ed/ Automatically adding global names to a module: how to do that, and alternatives to use when it's not a good idea: http://groups.google.com/group/comp.lang.python/t/40837c4567d64745/ Raymond Hettinger on the rationale behind the collections.Counter class: http://groups.google.com/group/comp.lang.python/t/64d0fe87f7ea9e6/ How Tk 8.5 + ttk (the version that ships with Python 2.6) compares to other GUI toolkits: http://groups.google.com/group/comp.lang.python/t/d8d24eacf022ed75/ The actual behavior of slicing like L[n::-1] is not properly documented: http://groups.google.com/group/comp.lang.python/t/add9aa920b55eacc/ Documenting a function with #comments instead of a proper docstring is silly, isn't it? How does that affect source code quality? (Including historical disgression going back to the PDP-8, the Altair and even nanocomputers...) http://groups.google.com/group/comp.lang.python/t/dea5c94f3d058e26/ Coming from Perl, one has to unlearn (bad?) habits and embrace Python's "rigid flexibility": http://groups.google.com/group/comp.lang.python/t/4bfdc60d3f58c960/ http://groups.google.com/group/comp.lang.python/t/24bfa00b428f868f/ And for those perl-like oneliner fans, here is dos2unix: http://groups.google.com/group/comp.lang.python/t/c4b63debe91d51c7/ Perl has CPAN. Python has PyPI + easy_install, but they lack many important features. How could we improve that? http://groups.google.com/group/comp.lang.python/t/c2c452cc4aaa6e98/ The pysandbox project provides a sandbox where untrusted code cannot modify its environment; now looking for someone to find holes in it: http://groups.google.com/group/comp.lang.python/t/87bf10f8acede7c3/ Everything Python-related you want is probably one or two clicks away in these pages: Python.org's Python Language Website is the traditional center of Pythonia http://www.python.org Notice especially the master FAQ http://www.python.org/doc/FAQ.html PythonWare complements the digest you're reading with the marvelous daily python url http://www.pythonware.com/daily Just beginning with Python? This page is a great place to start: http://wiki.python.org/moin/BeginnersGuide/Programmers The Python Papers aims to publish "the efforts of Python enthusiasts": http://pythonpapers.org/ The Python Magazine is a technical monthly devoted to Python: http://pythonmagazine.com Readers have recommended the "Planet" site: http://planet.python.org comp.lang.python.announce announces new Python software. Be sure to scan this newsgroup weekly. http://groups.google.com/group/comp.lang.py
Python-URL! - weekly Python news and links (Mar 17)
QOTW: "... [T]hat kills yet another usage of C ..." - Maciej Fijalkowski http://morepypy.blogspot.com/2009/11/some-benchmarking.html Making operations in the Fraction class automatically return a subclass instance when called with subclass arguments: http://groups.google.com/group/comp.lang.python/t/2512697a901d4752/ Providing alternate constructors for an existing class: http://groups.google.com/group/comp.lang.python/t/99e87afb58f3ef3d/ Checking existence of files matching a certain pattern: http://groups.google.com/group/comp.lang.python/t/a95183b7ae931b7a/ How to gracefully exit the current process, when there are multiple threads, on Windows: http://groups.google.com/group/comp.lang.python/t/5a6a7bcfd30fb7ce/ How inspect.stack()/sys._getframe() interact with local variables and references: http://groups.google.com/group/comp.lang.python/t/fc8bf697fa9a01a4/ Alternatives to the re module when looking for a large set of constant strings: http://groups.google.com/group/comp.lang.python/t/63e6e177be7dea21/ Why does Python syntax allow "break" from no more than a single loop at one time? http://groups.google.com/group/comp.lang.python/t/96f3407480ed39ab/ Trying to start a new Python meeting group is not easy: http://groups.google.com/group/comp.lang.python/t/a24bf882c72c555/ Bad interactions between cmd.exe code page (Windows), Popen, and the UTF-8 encoding: http://groups.google.com/group/comp.lang.python/t/2da1f1de573e5663/ An example showing how to use the locale module to format a number with thousand separators: http://groups.google.com/group/comp.lang.python/t/42e63e3a53f03593/ How non-ASCII characters get entered from the Python interactive console: http://groups.google.com/group/comp.lang.python/t/77271907fb195aca/ Raymond Hettinger on the rationale behind the collections.Counter class: http://groups.google.com/group/comp.lang.python/t/64d0fe87f7ea9e6/ You could not go to PyCon Atlanta? No problem - many PyCon talks from the last two years are available here: httppycon.blip.tv/ http://python.mirocommunity.org/ An interesting problem: find out the the algorithm used to compute a given CRC http://groups.google.com/group/comp.lang.python/t/b22db1e3e63db596/ Everything Python-related you want is probably one or two clicks away in these pages: Python.org's Python Language Website is the traditional center of Pythonia http://www.python.org Notice especially the master FAQ http://www.python.org/doc/FAQ.html PythonWare complements the digest you're reading with the marvelous daily python url http://www.pythonware.com/daily Just beginning with Python? This page is a great place to start: http://wiki.python.org/moin/BeginnersGuide/Programmers The Python Papers aims to publish "the efforts of Python enthusiasts": http://pythonpapers.org/ The Python Magazine is a technical monthly devoted to Python: http://pythonmagazine.com Readers have recommended the "Planet" site: http://planet.python.org comp.lang.python.announce announces new Python software. Be sure to scan this newsgroup weekly. http://groups.google.com/group/comp.lang.python.announce/topics Python411 indexes "podcasts ... to help people learn Python ..." Updates appear more-than-weekly: http://www.awaretek.com/python/index.html The Python Package Index catalogues packages. http://www.python.org/pypi/ Much of Python's real work takes place on Special-Interest Group mailing lists http://www.python.org/sigs/ Python Success Stories--from air-traffic control to on-line match-making--can inspire you or decision-makers to whom you're subject with a vision of what the language makes practical. http://www.pythonology.com/success The Python Software Foundation (PSF) has replaced the Python Consortium as an independent nexus of activity. It has official responsibility for Python's development and maintenance. http://www.python.org/psf/ Among the ways you can support PSF is with a donation. http://www.python.org/psf/donations/ The Summary of Python Tracker Issues is an automatically generated report summarizing new bugs, closed ones, and patch submissions. http://search.gmane.org/?author=status%40bugs.python.org&group=gmane.comp.python.devel&sort=date nullege is an interesting search Web application, with the intelligence to distinguish between Python code and comments. It provides what appear to be relevant results, and demands neither Java nor CSS be enabled: http://www.nullege.com Although unmaintained since 2002, the Cetus collection of Python hyperlinks retains a few gems.
Python-URL! - weekly Python news and links (Feb 9)
QOTW: "You see? That's what I like about the Python community: people even apologise for apologising :)" - Tim Golden http://groups.google.com/group/comp.lang.python/msg/858d1c31d0c2adff The third alpha version of Python 2.7 is ready for testing: http://groups.google.com/group/comp.lang.python/t/6f49dacfe8759508/ How to enumerate all possible strings matching a given regular expression: http://groups.google.com/group/comp.lang.python/t/1b78346c6661ac4f/ Which language features do you like most? http://groups.google.com/group/comp.lang.python/t/599b3c9772421ece/ Implementing a two-dimensional array in a simple way seems to actually be more efficient than other, more sophisticated alternatives: http://groups.google.com/group/comp.lang.python/t/55e595d6dc4ca3f4/ The new GIL (to be implemented in Python 3.2) will provide less overhead, especially in multicore CPUs: http://groups.google.com/group/comp.lang.python/t/586ef2d3685fa7ea/ In Python 3, 'exec' inside a function does not have the same effect as before: http://groups.google.com/group/comp.lang.python/t/7a046e4ede9c310a/ Using Queue objects to feed and synchronize several worker threads: http://groups.google.com/group/comp.lang.python/t/32256dd608c9c02/ New generation IDEs should provide much better and integrated refactoring tools: http://groups.google.com/group/comp.lang.python/t/e019614ea149e7bd/ There is no module in the standard library to handle filesystem paths in an OO way - but why? http://groups.google.com/group/comp.lang.pythonf580fb3763208425ece/ A "History Channel" special: how the way a TAB key was interpreted changed over time http://groups.google.com/group/comp.lang.python82d9181fcd31ffea3f4/ After a false start, finally we get our first "Is it Call-By-Value or Call-By-Reference?" thread of the year! http://groups.google.com/group/comp.lang.pythonfd36962c4970ac487ea/ Everything Python-related you want is probably one or two clicks away in these pages: Python.org's Python Language Website is the traditional center of Pythonia http://www.python.org Notice especially the master FAQ http://www.python.org/doc/FAQ.html PythonWare complements the digest you're reading with the marvelous daily python url http://www.pythonware.com/daily Just beginning with Python? This page is a great place to start: http://wiki.python.org/moin/BeginnersGuide/Programmers The Python Papers aims to publish "the efforts of Python enthusiasts": http://pythonpapers.org/ The Python Magazine is a technical monthly devoted to Python: http://pythonmagazine.com Readers have recommended the "Planet" site: http://planet.python.org comp.lang.python.announce announces new Python software. Be sure to scan this newsgroup weekly. http://groups.google.com/group/comp.lang.python.announce/topics Python411 indexes "podcasts ... to help people learn Python ..." Updates appear more-than-weekly: http://www.awaretek.com/python/index.html The Python Package Index catalogues packages. http://www.python.org/pypi/ Much of Python's real work takes place on Special-Interest Group mailing lists http://www.python.org/sigs/ Python Success Stories--from air-traffic control to on-line match-making--can inspire you or decision-makers to whom you're subject with a vision of what the language makes practical. http://www.pythonology.com/success The Python Software Foundation (PSF) has replaced the Python Consortium as an independent nexus of activity. It has official responsibility for Python's development and maintenance. http://www.python.org/psf/ Among the ways you can support PSF is with a donation. http://www.python.org/psf/donations/ The Summary of Python Tracker Issues is an automatically generated report summarizing new bugs, closed ones, and patch submissions. http://search.gmane.org/?author=status%40bugs.python.org&group=gmane.comp.python.devel&sort=date nullege is an interesting search Web application, with the intelligence to distinguish between Python code and comments. It provides what appear to be relevant results, and demands neither Java nor CSS be enabled: http://www.nullege.com Although unmaintained since 2002, the Cetus collection of Python hyperlinks retains a few gems. http://www.cetus-links.org/oo_python.html Python FAQTS http://python.faqts.com/ The Cookbook is a collaborative effort to capture useful and interesting recipes. http://code.activestate.com/recipes/langs/python/ Many Python conferences around the world are in preparation. Watch this space for links to them. Among several Python-oriented
Re: ctypes: delay conversion from c_char_p to string
Here's the method I was using. Note that tmp_char_ptr is of type c_void_p. This should avoid the memory leak, assuming I am interpreting the semantics of the cast correctly. Is there a cleaner way to do this with ctypes? def get_prop_string(self, prop_name): # Have to work with c_void_p to prevent ctypes from copying to a string # without giving me an opportunity to destroy the original string. tmp_char_ptr = _get_prop_string(self._props, prop_name) prop_val = cast(tmp_char_ptr, c_char_p).value _string_destroy(tmp_char_ptr) return prop_val On Wed, Apr 21, 2010 at 3:15 PM, Brendan Miller wrote: > I have a function exposed through ctypes that returns a c_char_p. > Since I need to deallocate that c_char_p, it's inconvenient that > ctypes copies the c_char_p into a string instead of giving me the raw > pointer. I believe this will cause a memory leak, unless ctypes is > smart enough to free the string itself after the copy... which I > doubt. > > Is there some way to tell ctypes to return an actual c_char_p, or is > my best bet to return a c_void_p and cast to c_char_p when I'm reading > to convert to a string? > > Thanks > Brendan > -- http://mail.python.org/mailman/listinfo/python-list
Re: Code redundancy
On Tue, 2010-04-20 at 14:43 +0100, Alan Harris-Reid wrote: > Hi, > > During my Python (3.1) programming I often find myself having to repeat > code such as... > > class1.attr1 = 1 > class1.attr2 = 2 > class1.attr3 = 3 > class1.attr4 = 4 > etc. > > Is there any way to achieve the same result without having to repeat the > class1 prefix? Before Python my previous main language was Visual > Foxpro, which had the syntax... > > with class1 >.attr1 = 1 >.attr2 = 2 >.attr3 = 3 >.attr4 = 4 >etc. > endwith > > Is there any equivalent to this in Python? Please don't take this as in invitation to disregard the excellent advice already received in this thread - I just want to point out that python can usually be bent to your will. Observe: from withhacks import namespace with namespace(class1): attr1 = 1 attr2 = 2 This will do pretty much what you get from the "with" statement in javascript (I assume it's similar to Visual Foxpro). But don't use this in any real code. Seriously, don't even think about it. You don't want to know the kind of abuses that go on under the covers to make this kind of syntax hacking work... Cheers, Ryan -- Ryan Kelly http://www.rfk.id.au | This message is digitally signed. Please visit r...@rfk.id.au| http://www.rfk.id.au/ramblings/gpg/ for details -- http://mail.python.org/mailman/listinfo/python-list
Re: Deleting more than one element from a list
Thanks for your reponses. -- http://mail.python.org/mailman/listinfo/python-list
Python-URL! - weekly Python news and links (Apr 21)
QOTW: "There's no RightAnswer(tm), just our best guess as to what is the most useful behavior for the most number of people." - Raymond Hettinger http://groups.google.com/group/comp.lang.python/msg/e7f78ef27811781b First beta version of Python 2.7 is available: http://groups.google.com.ar/group/comp.lang.python/t/d036954e11a264dd/ Why still a 2.7 release, when 3.1 is already out? http://groups.google.com.ar/group/comp.lang.python/t/f8a5028affe772ed/ Deciding when to pass around a parameter, and when to keep it as an instance attribute: http://groups.google.com.ar/group/comp.lang.python/t/6f51302327b58aac/ A class is more than just a container for functions and attributes: http://groups.google.com.ar/group/comp.lang.python/t/5525bd981dd9ece6/ Lie Ryan tries to explain the various escaping levels of a regular expression string: http://groups.google.com.ar/group/comp.lang.python/t/3a27b819307c0cb6/ Peter Otten shows how to make string.Template resolve dotted.names from nested dictionaries: http://groups.google.com.ar/group/comp.lang.python/t/d482f74d16fcbbb2/ Simple string operations, regular expressions, and a full blown parser: the right tools for different jobs http://groups.google.com.ar/group/comp.lang.python/t/888b3fe934e2c5e2/ The list comprehension loop variable, nested scopes, and common sense applied to programming languages: http://groups.google.com.ar/group/comp.lang.python/t/2b64b9a9069a324f/ Performance of list vs. set equality operations -- later: encapsulation, the Open/Closed principle, and why overriding __special__ methods may not affect certain built-in type operations: http://groups.google.com.ar/group/comp.lang.python/t/818d143c7e9550bc/ __del__ methods are not the same as C++ destructors; they might not even be called: http://groups.google.com.ar/group/comp.lang.python/t/6c875525954df888/ Abstract Base Classes affect the way issubclass() works -- it's not based only on the chain of MRO anymore: http://groups.google.com.ar/group/comp.lang.python/t/bd97c8e475e4da67/ wxPython and a bad example of 'property' usage: http://groups.google.com.ar/group/comp.lang.python/t/d88a387b5dca/ Keeping client expectations realistic and avoiding scope creep: http://www.gossamer-threads.com/lists/python/python/819932 Everything Python-related you want is probably one or two clicks away in these pages: Python.org's Python Language Website is the traditional center of Pythonia http://www.python.org Notice especially the master FAQ http://www.python.org/doc/FAQ.html PythonWare complements the digest you're reading with the marvelous daily python url http://www.pythonware.com/daily Just beginning with Python? This page is a great place to start: http://wiki.python.org/moin/BeginnersGuide/Programmers The Python Papers aims to publish "the efforts of Python enthusiasts": http://pythonpapers.org/ The Python Magazine is a technical monthly devoted to Python: http://pythonmagazine.com Readers have recommended the "Planet" site: http://planet.python.org comp.lang.python.announce announces new Python software. Be sure to scan this newsgroup weekly. http://groups.google.com/group/comp.lang.python.announce/topics Python411 indexes "podcasts ... to help people learn Python ..." Updates appear more-than-weekly: http://www.awaretek.com/python/index.html The Python Package Index catalogues packages. http://www.python.org/pypi/ Much of Python's real work takes place on Special-Interest Group mailing lists http://www.python.org/sigs/ Python Success Stories--from air-traffic control to on-line match-making--can inspire you or decision-makers to whom you're subject with a vision of what the language makes practical. http://www.pythonology.com/success The Python Software Foundation (PSF) has replaced the Python Consortium as an independent nexus of activity. It has official responsibility for Python's development and maintenance. http://www.python.org/psf/ Among the ways you can support PSF is with a donation. http://www.python.org/psf/donations/ The Summary of Python Tracker Issues is an automatically generated report summarizing new bugs, closed ones, and patch submissions. http://search.gmane.org/?author=status%40bugs.python.org&group=gmane.comp.python.devel&sort=date nullege is an interesting search Web application, with the intelligence to distinguish between Python code and comments. It provides what appear to be relevant results, and demands neither Java nor CSS be enabled: http://www.nullege.com Although unmaintained since 2002, the Cetus collection of P
Re: Code redundancy
Ryan Kelly wrote: On Tue, 2010-04-20 at 14:43 +0100, Alan Harris-Reid wrote: Hi, During my Python (3.1) programming I often find myself having to repeat code such as... class1.attr1 = 1 class1.attr2 = 2 class1.attr3 = 3 class1.attr4 = 4 etc. Is there any way to achieve the same result without having to repeat the class1 prefix? Before Python my previous main language was Visual Foxpro, which had the syntax... with class1 .attr1 = 1 .attr2 = 2 .attr3 = 3 .attr4 = 4 etc. endwith Is there any equivalent to this in Python? Please don't take this as in invitation to disregard the excellent advice already received in this thread - I just want to point out that python can usually be bent to your will. Observe: from withhacks import namespace with namespace(class1): attr1 = 1 attr2 = 2 This will do pretty much what you get from the "with" statement in javascript (I assume it's similar to Visual Foxpro). But don't use this in any real code. Seriously, don't even think about it. You don't want to know the kind of abuses that go on under the covers to make this kind of syntax hacking work... Cheers, Ryan Hi Ryan, thanks for that. No - I will not be adopting that solution. Is there anything Python can't do if you bend the rules far enough? ;-) Regards, Alan -- http://mail.python.org/mailman/listinfo/python-list
withhacks module (Re: Code redundancy)
Ryan, Your withhacks module looks very interesting. http://pypi.python.org/pypi/withhacks What are your specific concerns about its use? Are there portability concerns? Malcolm -- http://mail.python.org/mailman/listinfo/python-list
Re: withhacks module (Re: Code redundancy)
On Wed, 2010-04-21 at 19:43 -0400, pyt...@bdurham.com wrote: > Ryan, > > Your withhacks module looks very interesting. > http://pypi.python.org/pypi/withhacks > > What are your specific concerns about its use? Are there portability > concerns? It combines two things you just don't see in respectable python programs - bytecode hacking and trace-function hacking. And I'm sure its performance is less than stellar, although much of that could be fixed with some careful bytecode caching. I'd be surprised if it runs under alternative python implementations, and not surprised if it doesn't even work on Python 3 - although I haven't tried it to confirm either way. Having said that, it should work as advertised on Python 2.X with minimal fuss. So if you don't care about portability or about that dirty feeling you get from messing with the Python internals, then have at it :-) Cheers, Ryan -- Ryan Kelly http://www.rfk.id.au | This message is digitally signed. Please visit r...@rfk.id.au| http://www.rfk.id.au/ramblings/gpg/ for details -- http://mail.python.org/mailman/listinfo/python-list
Re: when should I explicitly close a file?
In message <4bc9aad...@dnews.tpgi.com.au>, Lie Ryan wrote: > Since in python nothing is guaranteed about implicit file close ... It is guaranteed that objects with a reference count of zero will be disposed. In my experiments, this happens immediately. -- http://mail.python.org/mailman/listinfo/python-list
Re: Download Proprietary Microsoft Products Now
In message , "Martin v. Löwis" wrote: > Brian Blais wrote: > >> On Apr 12, 2010, at 16:36 , Martin v. Loewis is wrote: >> >>> If you are planning to build Python extension modules in the next five >>> years, I recommend that you obtain a copy of VS Express >> >> Am I missing something here? I have heard this before, but I have built >> extension modules many times under windows (using Cython) and never once >> used a MS product. > > It's fine if your package supports being compiled with Mingw32. A lot of > source code can't be compiled this way, either because gcc doesn't > support some of the MS extensions (in particular wrt. COM) ... But then such code will not be portable to anything but Windows. > ... or because Mingw32 doesn't provide the header files (in particular > wrt. C++), or because linking with a library is necessary that uses the > MSVC mangling, not the g++ one (again, for C++). Again, that would be code that’s not portable off Windows. -- http://mail.python.org/mailman/listinfo/python-list
Re: when should I explicitly close a file?
On Wed, Apr 21, 2010 at 5:53 PM, Lawrence D'Oliveiro wrote: > In message <4bc9aad...@dnews.tpgi.com.au>, Lie Ryan wrote: > >> Since in python nothing is guaranteed about implicit file close ... > > It is guaranteed that objects with a reference count of zero will be > disposed. > In my experiments, this happens immediately. Experiment with an implementation other than CPython and prepare to be surprised. Cheers, Chris -- http://blog.rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
Re: withhacks module (Re: Code redundancy)
Ryan, > So if you don't care about portability or about that dirty feeling you get > from messing with the Python internals, then have at it :-) Warnings aside, its very clever code. Thanks for sharing! Malcolm -- http://mail.python.org/mailman/listinfo/python-list
Re: Download Proprietary Microsoft Products Now
In message <4bc8547...@dnews.tpgi.com.au>, Lie Ryan wrote: > ... so you should get the full installer if you want to insure yourself > from Microsoft pulling the plug out. I wonder how many Windows users will be able to figure that out... -- http://mail.python.org/mailman/listinfo/python-list
Re: Download Proprietary Microsoft Products Now
On Thu, Apr 22, 2010 at 9:59 AM, Lawrence D'Oliveiro wrote: >> ... or because Mingw32 doesn't provide the header files (in particular >> wrt. C++), or because linking with a library is necessary that uses the >> MSVC mangling, not the g++ one (again, for C++). > > Again, that would be code that’s not portable off Windows. Not really, part of the issue is that mingw uses ancient gcc (3.x series), and g++ 3.x has poor C++ support compared to MSVC (or gcc 4.x). There is also the issue that gcc debugging symbols are totally incompatible with MSVC, so you cannot debug things from anything but gdb. Gcc for win64 is also not that stable yet - when porting numpy and scipy on windows 64, I got numerous issues with it. None of this has anything to do with portability. cheers, David -- http://mail.python.org/mailman/listinfo/python-list
