Re: isinstance(False, int)
Rolando Espinoza La Fuente a écrit : On Fri, Mar 5, 2010 at 2:32 PM, mk wrote: Arnaud Delobelle wrote: 1 == True True 0 == False True So what's your question? Well nothing I'm just kind of bewildered: I'd expect smth like that in Perl, but not in Python.. Although I can understand the rationale after skimming PEP 285, I still don't like it very much. So, the pythonic way to check for True/False should be: 1 is True False 0 is False False instead of ==, right? Nope. The pythonic way is to check for truth value - not for True or False -, and to only use the identity test when wanting to test for identity. -- http://mail.python.org/mailman/listinfo/python-list
libc Sleep api performs a busy waiting
Hi,
I am having a problem while using sleep function from libc , the
thread in which i am calling it is getting struck and not allowing
other threads to execute. Here is a simple code that i am trying to
exeute
import threading
import time
import dl
def dummy1():
a=dl.open('/lib/libc.so.6')
print "in thread 1 Start"
a.call('sleep',2)
#time.sleep(2)
print "in thread 1 End"
def dummy2():
print "in thread 2 Start"
time.sleep(1)
print "in thread 2 End"
newThread1=threading.Thread(None,dummy1)
newThread2=threading.Thread(None,dummy2)
newThread1.start()
newThread2.start()
print "in main"
The out put of this program is (In this case thread 1 even though i
am calling a sleep function its not allowing other threads to execute,
other threads execute only after the completion of first thread)
in thread 1 Start
in thread 1 End
in thread 2 Start
in main
in thread 2 End
where as if i use time.sleep instead of a.call(sleep) the out put is
(which i guess is right behaviour, because it start the threads and
suspends them because the have sleep , and continue executing the main
thread)
in thread 1 Start
in thread 2 Start
in main
in thread 2 End
in thread 1 End
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Re: The C language like the Python, by the Python and for the Python--- PythoidC
Dear Stefan, Thanks a lot for your interest in PythoidC. Yes, PythoidC takes regular expression to parse C header files, but there is no danger at all, because, the parsed result is only used for introspecting and auto-completion, has noting to do with syntax converting and compiling. I just improved PythoidC to a satisfying version for me, up to now, all the projects with PythoidC are experimental or educational. PythoidC is mainly used to deal with simple but time consuming tasks in Python project, as you see, PythoidC file can be imported the same any Python files. Oliver ( ChenGuang ) ? CHEN Guang, 08.03.2010 06:08: > Hi, if you are interested in C-Python mixed programming, please take a look > at: > http://pythoidc.googlecode.com > PythoidC is the C language like the Python, by the Python and for the Python It looks a bit dangerous to me to parse C header files only with regular expressions. For Cython, some people seem to be using gcc-xml instead, and some have reported that clang is really nice to play with. However, none of those has made its way into Cython yet, mostly due to the dependency it would add. I don't know if tcc (which you seem to depend on) has anything comparable, but I doubt it. Just out of curiosity, is this syntax converter actually used for any real projects? Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: running a program on many processors
On Mar 8, 1:18 am, Paweł Banyś wrote: > Hello, > > I have already read about Python and multiprocessing which allows using > many processors. The idea is to split a program into separate tasks and > run each of them on a separate processor. However I want to run a Python > program doing a single simple task on many processors so that their > cumulative power is available to the program as if there was one huge > CPU instead of many separate ones. Is it possible? How can it be achieved? > > Best regards, > > Paweł I can suggest you to try some .NET language (like c#, Boo <-- python- like, or maybe even IronPython). Reason is that .NET languages do analyze the code and split them into logical parts that run across threads. -- http://mail.python.org/mailman/listinfo/python-list
libc Sleep api performs a busy waiting
Hi ,
I am having a problem while using sleep function from libc , the
thread in which i am calling it is getting struck and not allowing
other threads to execute. Here is a simple code that i am trying to
exeute
import threading
import time
import dl
def dummy1():
a=dl.open('/lib/libc.so.6')
print "in thread 1 Start"
a.call('sleep',2)
#time.sleep(2)
print "in thread 1 End"
def dummy2():
print "in thread 2 Start"
time.sleep(1)
print "in thread 2 End"
newThread1=threading.Thread(None,dummy1)
newThread2=threading.Thread(None,dummy2)
newThread1.start()
newThread2.start()
print "in main"
The out put of this program is (In this case thread 1 even though i
am calling a sleep function its not allowing other threads to execute,
other threads execute only after the completion of first thread)
in thread 1 Start
in thread 1 End
in thread 2 Start
in main
in thread 2 End
where as if i use time.sleep instead of a.call(sleep) the out put is
(which i guess is right behaviour, because it start the threads and
suspends them because the have sleep , and continue executing the main
thread)
in thread 1 Start
in thread 2 Start
in main
in thread 2 End
in thread 1 End
Can any of you point me how to over come this.?
Thanks
Mahesh
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Re: Reverse engineering CRC?
Steven D'Aprano wrote: On Mon, 08 Mar 2010 16:09:12 +1300, Gregory Ewing wrote: Given some known data/crc pairs, how feasible is it to figure out the polynomial being used to generate the crc? Google is your friend: http://www.woodmann.com/fravia/crctut1.htm That page was interesting to read, especially since I've implemented the three algorithms - CRC16, CRC32, and the reversed version of CRC16, all in the long-distant past. However, if there's anything in there about how to derive the polynomial algorithm from (a few) samples I missed it entirely. Instead, what it calls reverse engineering is figuring out how to modify a message to force it to have a desired CRC value (when the CRC polynomial is already known). DaveA -- http://mail.python.org/mailman/listinfo/python-list
Re: Best practice way to detect internet connectivity under Python 2.6/Windows
On 08/03/2010 02:41, pyt...@bdurham.com wrote: Is the best pratice way to detect internet connectivity under Windows (using Python 2.6) simply to attempt to access a known internet website using urllib or urlib2 wrapped in a try/except construct? Well, in theory you could use the Internet API: http://msdn.microsoft.com/en-us/library/aa383996%28VS.85%29.aspx which is exposed via the win32inet module: http://timgolden.me.uk/pywin32-docs/win32inet.html but I'd just do a socket connection to port 80 (or some known port on some known server) with a reasonable timeout. TJG -- http://mail.python.org/mailman/listinfo/python-list
Re: Curiosity stirkes me on 'import this'.
> I took a look at the 'this' module to see where the file is stored. This is > probably old news to some people, but was new to me. > > print this.s > Gur Mra bs Clguba, ol Gvz Crgref > > Ornhgvshy vf orggre guna htyl. > Rkcyvpvg vf orggre guna vzcyvpvg. > Fvzcyr vf orggre guna pbzcyrk. > Pbzcyrk vf orggre guna pbzcyvpngrq. > Syng vf orggre guna arfgrq. > Fcnefr vf orggre guna qrafr. > Ernqnovyvgl pbhagf. > Fcrpvny pnfrf nera'g fcrpvny rabhtu gb oernx gur ehyrf. > Nygubhtu cenpgvpnyvgl orngf chevgl. > Reebef fubhyq arire cnff fvyragyl. > Hayrff rkcyvpvgyl fvyraprq. > Va gur snpr bs nzovthvgl, ershfr gur grzcgngvba gb thrff. > Gurer fubhyq or bar-- naq cersrenoyl bayl bar --boivbhf jnl gb qb vg. > Nygubhtu gung jnl znl abg or boivbhf ng svefg hayrff lbh'er Qhgpu. > Abj vf orggre guna arire. > Nygubhtu arire vf bsgra orggre guna *evtug* abj. > Vs gur vzcyrzragngvba vf uneq gb rkcynva, vg'f n onq vqrn. > Vs gur vzcyrzragngvba vf rnfl gb rkcynva, vg znl or n tbbq vqrn. > Anzrfcnprf ner bar ubaxvat terng vqrn -- yrg'f qb zber bs gubfr! > > And some other attributes in 'this' module as well, that decodes the string. > I'm curious. Was this encoded purely for fun? Yes. Cheers, Daniel -- Psss, psss, put it down! - http://www.cafepress.com/putitdown -- http://mail.python.org/mailman/listinfo/python-list
Re: Reverse engineering CRC?
Steven D'Aprano wrote: Can you just ask the application developer what CRC is being used? Or look at the source code? Disassemble the binary? There's no source, and the binary is enormous. I could ask, but I wouldn't hold out much hope of them being willing to tell me. it appears that the crc size may be at least 24 bits, so just trying all possible polynomials probably isn't doable. "At least"? Can't you tell by looking at them? It's not entirely clear exactly which bytes are part of the CRC. There are 3 adjacent bytes in the header of the file that change when I modify the contents, which led me to think it was a 24-bit CRC. But I now believe that one of them is not part of the CRC, and it's actually 16 bits. Using pycrc, I've now tried all possible 16-bit polynomials, with various combinations of bit and byte reversal, but I haven't found one that works consistently, so I'm wondering whether it's using some non-standard algorithm. -- Greg -- http://mail.python.org/mailman/listinfo/python-list
Re: negative "counts" in collections.Counter?
2010/3/8 Raymond Hettinger :
> On Mar 7, 5:46 pm, Steven D'Aprano cybersource.com.au> wrote:
>> Given that Counter supports negative counts, it looks to me that the
>> behaviour of __add__ and __sub__ is fundamentally flawed. You should
>> raise a bug report (feature enhancement) on the bug tracker.
>
> It isn't a bug. I designed it that way.
> There were several possible design choices,
> each benefitting different use cases.
>...
> One possible choice (the one preferred by the OP) was to
> has addition and subtraction be straight adds and subtracts
> without respect to sign and to not support __and__ and __or__.
> Straight addition was already supported via the update() method.
> But no direct support was provided for straight subtractions
> that leave negative values. Sorry about that.
>
> Instead the choice was to implement the four methods as
> multiset operations. As such, they need to correspond
> to regular set operations. For example, with sets:
>
>...
> Hopes this gives you some insight into the design choices.
>
>
> Raymond Hettinger
>
Thank you very much for the exhaustive explanation Raymond!
I very much suspected, there would be some exact reasoning behind it,
as these negative counts are explicitly handled in the code of these
methods.
I just happened to expect the straightforward addition and subtraction
and possibly the zero truncation or an exception in incompatible cases
(like elements() with floats, currently). This way also the negative
part would be available and the truncation possible.
I am by far not able to follow all of the mathematical background, but
even for zero-truncating multiset, I would expect the truncation on
input rather than on output of some operations. E.g. the following
seems surprising to me in context of the discarded negatives by
addition or subtraction:
>>> c1=collections.Counter({'a': -11, 'b': -8})
>>> c2=collections.Counter({'a': 3})
>>> c2-c1
Counter({'a': 14, 'b': 8})
>>>
Probably a kind of negative_update() or some better named method will
be handy, like the one you supplied or simply the current module code
without the newcount > 0: ... condition. Or would it be an option to
have a keyword argument like zero_truncate=False which would influence
this behaviour? Or is some other method than elements() incompatible
with negative counts?
(I actually can imagine comparing negative counts on both sides. e.g.
in a secondary comparison of two wordlists with specific removed items
- comparing to the "master" list.)
Additionally, were issubset and issuperset considered for this
interface (not sure whether symmetric_difference would be applicable)?
Anyway, I recognise, that I can easily use a custom class for these
tasks, if these usecases are rare or non-standard for this general
collection object.
Thanks again,
vbr
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Re: Curiosity stirkes me on 'import this'.
Daniel Fetchinson writes: > > I'm curious. Was this encoded purely for fun? > > Yes. For some more fun, try measuring the ‘this’ module source code against the principles in the Zen. -- \ “Leave nothing to chance. Overlook nothing. Combine | `\ contradictory observations. Allow yourself enough time.” | _o__) —Hippocrates | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: negative "counts" in collections.Counter?
On Sun, 07 Mar 2010 22:31:00 -0800, Raymond Hettinger wrote: > On Mar 7, 5:46 pm, Steven D'Aprano cybersource.com.au> wrote: >> Given that Counter supports negative counts, it looks to me that the >> behaviour of __add__ and __sub__ is fundamentally flawed. You should >> raise a bug report (feature enhancement) on the bug tracker. > > It isn't a bug. I designed it that way. There were several possible > design choices, each benefitting different use cases. Thanks for the explanation Raymond. A few comments follow: > FWIW, here is the reasoning behind the design. > > The basic approach to Counter() is to be a dict subclass that supplies > zero for missing values. This approach places almost no restrictions > on what can be stored in it. You can store floats, decimals, fractions, > etc. Numbers can be positive, negative, or zero. Another way of using default values in a dict. That's five that I know of: dict.get, dict.setdefault, dict.pop, collections.defaultdict, and collections.Counter. And the Perl people criticise Python for having "only one way to do it" *wink* (That's not meant as a criticism, merely an observation.) [...] > One possible choice (the one preferred by the OP) was to has addition > and subtraction be straight adds and subtracts without respect to sign > and to not support __and__ and __or__. Straight addition was already > supported via the update() method. But no direct support was provided > for straight subtractions that leave negative values. Sorry about that. Would you consider a feature enhancement adding an additional method, analogous to update(), to perform subtractions? I recognise that it's easy to subclass and do it yourself, but there does seem to be some demand for it, and it is an obvious feature given that Counter does support negative counts. > Instead the choice was to implement the four methods as multiset > operations. As such, they need to correspond to regular set operations. Personally, I think the behaviour of + and - would be far less surprising if the class was called Multiset. Intuitively, one would expect counters to be limited to ints, and to support negative counts when adding and subtracting. In hindsight, do you think that Multiset would have been a better name? -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: A "scopeguard" for Python
Alf P. Steinbach wrote: > * Gabriel Genellina: >> En Thu, 04 Mar 2010 20:52:04 -0300, Alf P. Steinbach >> escribió: >> >>> Sorry, as with the places noted above, I can't understand what you're >>> trying to say here. >> >> Regarding your posts, neither can I. All the time. Sorry, deciphering >> your posts would force me to spend much more time than available and I >> can't afford that - so I'm blocking your messages from now on. > > > You could just ask if there was anything you didn't understand. > > Even with as little you quote readers can see my approach to that > problem: asking. > > But your response, both the out of context quoting and your comment, > seems solely designed to convey a negative impression instead of > addressing any technical issue. > This isn't an isolated case, Alf. Physician, heal thyself. regards Steve -- Steve Holden +1 571 484 6266 +1 800 494 3119 PyCon is coming! Atlanta, Feb 2010 http://us.pycon.org/ Holden Web LLC http://www.holdenweb.com/ UPCOMING EVENTS:http://holdenweb.eventbrite.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: libc Sleep api performs a busy waiting
Mahesh wrote:
> Hi,
>
> I am having a problem while using sleep function from libc , the
> thread in which i am calling it is getting struck and not allowing
> other threads to execute. Here is a simple code that i am trying to
> exeute
>
> import threading
> import time
> import dl
>
>
> def dummy1():
> a=dl.open('/lib/libc.so.6')
> print "in thread 1 Start"
> a.call('sleep',2)
> #time.sleep(2)
> print "in thread 1 End"
>
> def dummy2():
> print "in thread 2 Start"
> time.sleep(1)
> print "in thread 2 End"
> newThread1=threading.Thread(None,dummy1)
> newThread2=threading.Thread(None,dummy2)
> newThread1.start()
> newThread2.start()
>
> print "in main"
>
>
>
> The out put of this program is (In this case thread 1 even though i
> am calling a sleep function its not allowing other threads to execute,
> other threads execute only after the completion of first thread)
>
> in thread 1 Start
> in thread 1 End
> in thread 2 Start
> in main
> in thread 2 End
>
>
> where as if i use time.sleep instead of a.call(sleep) the out put is
> (which i guess is right behaviour, because it start the threads and
> suspends them because the have sleep , and continue executing the main
> thread)
> in thread 1 Start
> in thread 2 Start
> in main
> in thread 2 End
> in thread 1 End
>
>
Why not just use the time module's sleep function? Unlike the libc code
it releases Python's GIL (global interpreter lock), thus allowing other
threads to run.
regards
Steve
--
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PyCon is coming! Atlanta, Feb 2010 http://us.pycon.org/
Holden Web LLC http://www.holdenweb.com/
UPCOMING EVENTS:http://holdenweb.eventbrite.com/
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Re: Conditional based on whether or not a module is being used
Pete Emerson wrote: On Mar 5, 1:14 pm, Chris Rebert wrote: On Fri, Mar 5, 2010 at 12:25 PM, Pete Emerson wrote: On Fri, Mar 5, 2010 at 12:17 PM, Chris Rebert wrote: On 3/5/10, Pete Emerson wrote: In a module, how do I create a conditional that will do something based on whether or not another module has been loaded? If someone is using foo module, I want to take advantage of its features and use it in foobar, otherwise, I want to do something else. In other words, I don't want to create a dependency of foobar on foo. My failed search for solving this makes me wonder if I'm approaching this all wrong. Just try importing foo, and then catch the exception if it's not installed. Except I want to use the module only if the main program is using it too, not just if it's available for use. I think that I found a way in my follow-up post to my own message, but not sure it's the best way or conventional. What is your use case for this behavior exactly? You've piqued my curiosity. Cheers, Chris --http://blog.rebertia.com I have written my first module called "logger" that logs to syslog via the syslog module but also allows for logging to STDOUT in debug mode at multiple levels (to increase verbosity depending on one's need), or both. I've looked at the logging module and while it might suit my needs, it's overkill for me right now (I'm still *very* much a python newbie). I want to write other modules, and my thinking is that it makes sense for those modules to use the "logger" module to do the logging, if and only if the parent using the other modules is also using the logger module. In other words, I don't want to force someone to use the "logger" module just so they can use my other modules, even if the "logger" module is installed ... but I also want to take advantage of it if I'm using it. Now that I've written that, I'm not sure that makes a whole lot of sense. It seems like I could say, "hey, this person has the 'logger' module available, let's use it!". Thoughts? The logging module is not overkill, use it. It can be simple if you want it to be, and can be more complex if you need advanced logging features. All the "what if the application is not using my logger module" is dealt with by the logging module. And I'm not its designer in any way, so my advice is completely objective :-) It's definitely worth spending some time ramping up with it. JM -- http://mail.python.org/mailman/listinfo/python-list
Re: Reverse engineering CRC?
Gregory Ewing wrote: Steven D'Aprano wrote: Can you just ask the application developer what CRC is being used? Or look at the source code? Disassemble the binary? There's no source, and the binary is enormous. I could ask, but I wouldn't hold out much hope of them being willing to tell me. it appears that the crc size may be at least 24 bits, so just trying all possible polynomials probably isn't doable. "At least"? Can't you tell by looking at them? It's not entirely clear exactly which bytes are part of the CRC. There are 3 adjacent bytes in the header of the file that change when I modify the contents, which led me to think it was a 24-bit CRC. But I now believe that one of them is not part of the CRC, and it's actually 16 bits. Using pycrc, I've now tried all possible 16-bit polynomials, with various combinations of bit and byte reversal, but I haven't found one that works consistently, so I'm wondering whether it's using some non-standard algorithm. Or even some other standard algorithm. If you know so little about the value, how do you even know it's a CRC ? Could it be a ones-complement sum, such as used in Ethernet? Is the problem really worth it? The possibilities are practically unbounded. And if the developer is really determined to make it difficult, they could be doing multiple passes over the data, in which case probably disassembly (or subtle debug tracing) may be your best bet. DaveA Dave -- http://mail.python.org/mailman/listinfo/python-list
Re: Import problem
Johny wrote:
I have this directory structure
C:
\A
__init__.py
amodule.py
\B
__init__.py
bmodule.py
\D
__init__.py
dmodule.py
and I want to import bmodule.py
C:\>cd \
C:\>python
Python 2.5 (r25:51908, Sep 19 2006, 09:52:17) [MSC v.1310 32 bit
(Intel)] on win
32
Type "help", "copyright", "credits" or "license" for more information.
from A.B import bmodule
I am bmodule
C:\>
so far so good. Now I would like to import bmodule but if the current
directory is \D subdirectory.
C:> cd \A\B\D
C:\A\B\D>
C:\A\B\D>python
Python 2.5 (r25:51908, Sep 19 2006, 09:52:17) [MSC v.1310 32 bit
(Intel)] on win
32
Type "help", "copyright", "credits" or "license" for more information.
import sys
sys.path.append('C:\\A')
from A.B import bmodule
Traceback (most recent call last):
File "", line 1, in
ImportError: No module named A.B
C:\>
so I can not import a module from the parent directory? Or where did I
make an error?
Thanks for help
L.
try
import sys
sys.path.append('C:\\')
from A.B import bmodule
JM
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What to do if anything bites.
What to do if anything bites. Check our bites treatment at http://108ambulance.blogspot.com/2010/03/108-ambulance-home-page.html -- http://mail.python.org/mailman/listinfo/python-list
ANNOUNCE: Major Feature Release - NHI1-0.7, PLMK-1.6 and libmsgque-4.5
Dear User, ANNOUNCE:Major Feature Release libmsgque: Application-Server-Toolkit for C, C++, JAVA, C#, TCL, PERL, PYTHON, VB.NET PLMK: Programming-Language-Microkernel NHI1: Non-Human-Intelligence #1 SUMMARY === This is a 'major-feature-release' to add 'longtime-transaction' support. A 'longtime-transaction' is a transaction with a possible infinite time period between the start and the end. A 'longtime-transaction' is always a 'persistent-transaction' too. The 'persistent' support is available as an in-memory solution on the 'application-server' or in an additional 'bidirectional-filter' available for the next release. A typical scenario for a 'longtime-transaction' is: * A user with a client connect to the server and start a 'longtime-transaction' job. After a while the user shutdown the client and leave the office. At the next morning the user start the client again and the results are send from the server to the client. * On a space mission the time-overhead between transaction start and end is large. It is usually not possible to keep the client-server-connection open all the time. * On a military action-system the enemy try to interrupted the client-server-connection to disable data communication. To use a 'longtime-transaction' the results are send to a 'client-service' registered with MqServiceCreate. This service and addtional data (I call this data 'local-context-data') have to be added to the 'longterm-transaction' package to be available in the result. On the 'link-target' the 'local-context-data' is initial stripped from the 'data-package' and is later added to the results again. The 'local-context-data' is added to the 'data-package' with MqSendT_START and MqSendT_END. The 'local-context-data' is read from the 'data-package' with MqReadT_START and MqReadT_END. LINKS = libmsgque: > http://nhi1.berlios.de/theLink/index.htm NHI1: > http://nhi1.berlios.de/ DOWNLOAD: > http://developer.berlios.de/projects/nhi1/ mfg Andreas Otto (aotto1968) -- http://mail.python.org/mailman/listinfo/python-list
Re: A "scopeguard" for Python
On Mar 8, 2010, at 7:28 AM, Steve Holden wrote: >> >> But your response, both the out of context quoting and your comment, >> seems solely designed to convey a negative impression instead of >> addressing any technical issue. >> > This isn't an isolated case, Alf. Physician, heal thyself. As far as I can tell, this happens on every thread Alf is involved in at one point or another. I'm sure it's "everyone else." S -- http://mail.python.org/mailman/listinfo/python-list
Re: NoSQL Movement?
many people mentioned scalibility... though i think it is fruitful to talk about at what size is the NoSQL databases offer better scalability than SQL databases. For example, consider, if you are within world's top 100th user of database in terms of database size, such as Google, then it may be that the off-the-shelf tools may be limiting. But how many users really have such massive size of data? note that google's need for database today isn't just a seach engine. It's db size for google search is probably larger than all the rest of search engine company's sizes combined. Plus, there's youtube (vid hosting), gmail, google code (source code hosting), google blog, orkut (social networking), picasa (photo hosting), etc, each are all ranked within top 5 or so with respective competitors in terms of number of accounts... so, google's datasize is probably number one among the world's user of databases, probably double or triple than the second user with the most large datasize. At that point, it seems logical that they need their own db, relational or not. Xah ∑ http://xahlee.org/ ☄ On Mar 4, 10:35 pm, John Nagle wrote: > Xah Lee wrote: > > recently i wrote a blog article on The NoSQL Movement > > athttp://xahlee.org/comp/nosql.html > > > i'd like to post it somewhere public to solicit opinions, but in the > > 20 min or so, i couldn't find a proper newsgroup, nor private list > > that my somewhat anti-NoSQL Movement article is fitting. > > Too much rant, not enough information. > > There is an argument against using full relational databases for > some large-scale applications, ones where the database is spread over > many machines. If the database can be organized so that each transaction > only needs to talk to one database machine, the locking problems become > much simpler. That's what BigTable is really about. > > For many web applications, each user has more or less their own data, > and most database activity is related to a single user. Such > applications can easily be scaled up with a system that doesn't > have inter-user links. There can still be inter-user references, > but without a consistency guarantee. They may lead to dead data, > like Unix/Linux symbolic links. This is a mechanism adequate > for most "social networking" sites. > > There are also some "consistent-eventually" systems, where a query > can see old data. For non-critical applications, those can be > very useful. This isn't a SQL/NoSQL thing; MySQL asynchronous > replication is a "consistent-eventually" system. Wikipedia uses > that for the "special" pages which require database lookups. > > If you allow general joins across any tables, you have to have all > the very elaborate interlocking mechanisms of a distributed database. > The serious database systems (MySQL Cluster and Oracle, for example) > do offer that, but there are usually > substantial complexity penalties, and the databases have to be carefully > organized to avoid excessive cross-machine locking. If you don't need > general joins, a system which doesn't support them is far simpler. > > John Nagle -- http://mail.python.org/mailman/listinfo/python-list
Converting HTML to PDF using Python?
Hi Python superstars, Guys, any ideas on how to convert HTML files to PDF files? Or as an alternative, how to convert HTML files to an image file(jpeg/png/etc)? Ideally, the converted PDF/Image file should like exactly like the way HTML file looks in the browser. I really have no idea about this so I will really appreciate all the help. Thanks in advance and kindly pardon my ignorance. Thanks, Oltmans -- http://mail.python.org/mailman/listinfo/python-list
Re: negative "counts" in collections.Counter?
On Mon, Mar 8, 2010 at 4:21 AM, Steven D'Aprano < st...@remove-this-cybersource.com.au> wrote: > On Sun, 07 Mar 2010 22:31:00 -0800, Raymond Hettinger wrote: >> On Mar 7, 5:46 pm, Steven D'Aprano > cybersource.com.au> wrote: >>> Given that Counter supports negative counts, it looks to me that the >>> behaviour of __add__ and __sub__ is fundamentally flawed. You should >>> raise a bug report (feature enhancement) on the bug tracker. >> >> It isn't a bug. I designed it that way. There were several possible >> design choices, each benefitting different use cases. >> Instead the choice was to implement the four methods as multiset >> operations. As such, they need to correspond to regular set operations. > > Personally, I think the behaviour of + and - would be far less surprising > if the class was called Multiset. Intuitively, one would expect counters > to be limited to ints, and to support negative counts when adding and > subtracting. In hindsight, do you think that Multiset would have been a > better name? Of course I'm not Raymond, but I'd encourage reading the original announcement thread where that and related issues were discussed: http://mail.python.org/pipermail/python-list/2009-January/1189466.html To summarize the arguments against "Multiset": * the API is primarily dict-like, not set-like ** related to this, len() and .items() don't behave in what is arguably an "intuitive" way for multisets * the API allows for negative counts; sets don't normally allow negative multiplicities The same pretty much also goes for why "Bag" wouldn't be an appropriate name. Finally, it leaves the names available for when a proper Bag/Multiset is added. :) Cheers, Chris -- http://blog.rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
Trouble with quotes
Hi,
I've written some (primitive) code to parse some apache logfies and
establish if apache has appended a session cookie to the end. We're
finding that some browsers don't and apache doesn't just append a "-"
- it just omits it.
It's working fine, but for an edge case:
Couldn't match 192.168.1.107 - - [24/Feb/2010:20:30:44 +0100] "GET
http://sekrit.com/node/175523 HTTP/1.1" 200 -
"http://sekrit.com/search/results/"3%2B2%20course""; "Mozilla/4.0
(compatible; MSIE 6.0; Windows NT 5.1; SV1; GTB6.4)"
Couldn't match 192.168.1.107 - - [24/Feb/2010:20:31:15 +0100] "GET
http://sekrit.com/node/175521 HTTP/1.1" 200 -
"http://sekrit.com/search/results/"3%2B2%20course""; "Mozilla/4.0
(compatible; MSIE 6.0; Windows NT 5.1; SV1; GTB6.4)"
Couldn't match 192.168.1.107 - - [24/Feb/2010:20:32:07 +0100] "GET
http://sekrit.com/node/175520 HTTP/1.1" 200 -
"http://sekrit.com/search/results/"3%2B2%20course""; "Mozilla/4.0
(compatible; MSIE 6.0; Windows NT 5.1; SV1; GTB6.4)"
Couldn't match 192.168.1.107 - - [24/Feb/2010:20:32:33 +0100] "GET
http://sekrit.com/node/175522 HTTP/1.1" 200 -
"http://sekrit.com/search/results/"3%2B2%20course""; "Mozilla/4.0
(compatible; MSIE 6.0; Windows NT 5.1; SV1; GTB6.4)"
Couldn't match 192.168.1.107 - - [24/Feb/2010:20:33:01 +0100] "GET
http://sekrit.com/node/175527 HTTP/1.1" 200 -
"http://sekrit.com/search/results/"3%2B2%20course""; "Mozilla/4.0
(compatible; MSIE 6.0; Windows NT 5.1; SV1; GTB6.4)"
Couldn't match 192.168.1.107 - - [25/Feb/2010:17:01:54 +0100] "GET
http://sekrit.com/search/results/ HTTP/1.0" 200 -
"http://sekrit.com/search/results/"guideline%20grids"&page=1";
"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR
1.1.4322; .NET CLR 2.0.50727)"
Couldn't match 192.168.1.107 - - [25/Feb/2010:17:02:15 +0100] "GET
http://sekrit.com/search/results/ HTTP/1.0" 200 -
"http://sekrit.com/search/results/"guideline%20grids"&page=1";
"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR
1.1.4322; .NET CLR 2.0.50727)"
If there are " " inside the request string, my regex breaks.
Here's the code:
#!/usr/bin/env python
import re
pattern =
r'(?P^(-|[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}(,
[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})*){1})
(?P(\S*)) (?P(\S*))
(?P(\[[^\]]+\]))
(?P(\"([^"\\]*(?:\\.[^"\\]*)*)\")?)
(?P(\S*)) (?P(\S*))
(?P(\"([^"\\]*(?:\\.[^"\\]*)*)\")?)
(?P(\"([^"\\]*(?:\\.[^"\\]*)*)\")?)(
)?(?P(\"([^"\\]*(?:\\.[^"\\]*)*)\")?)'
regex = re.compile(pattern)
lines = 0
no_cookies = 0
unmatched = 0
for line in open('/home/stephen/scratch/test-data.txt'):
lines +=1
line = line.strip()
match = regex.match(line)
if match:
data = match.groupdict()
if data['SiteIntelligenceCookie'] == '':
no_cookies +=1
else:
print "Couldn't match ", line
unmatched +=1
print "I analysed %s lines." % (lines,)
print "There were %s lines with missing Site Intelligence cookies." %
(no_cookies,)
print "I was unable to process %s lines." % (unmatched,)
How can I make the regex a bit more resilient so it doesn't break when
" " is embedded?
--
Stephen Nelson-Smith
Technical Director
Atalanta Systems Ltd
www.atalanta-systems.com
--
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Re: Trouble with quotes
On 03/08/10 17:06, Stephen Nelson-Smith wrote:
Hi,
I've written some (primitive) code to parse some apache logfies and
establish if apache has appended a session cookie to the end. We're
finding that some browsers don't and apache doesn't just append a "-"
- it just omits it.
It's working fine, but for an edge case:
Couldn't match 192.168.1.107 - - [24/Feb/2010:20:30:44 +0100] "GET
http://sekrit.com/node/175523 HTTP/1.1" 200 -
"http://sekrit.com/search/results/"3%2B2%20course""; "Mozilla/4.0
(compatible; MSIE 6.0; Windows NT 5.1; SV1; GTB6.4)"
I didn't try to mentally parse the regex pattern (I like to keep
reasonably sane). However from the sounds of it the script barfs when
there is a quoted part in the second URL part. So how about doing a
simple string.replace('/"','') & string.replace('" ','') before doing
your re foo?
--
mph
--
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Re: Converting HTML to PDF using Python?
On Mar 8, 10:36 am, Oltmans wrote: > Hi Python superstars, > > Guys, any ideas on how to convert HTML files to PDF files? Or as an > alternative, how to convert HTML files to an image file(jpeg/png/etc)? > Ideally, the converted PDF/Image file should like exactly like the way > HTML file looks in the browser. > > I really have no idea about this so I will really appreciate all the > help. Thanks in advance and kindly pardon my ignorance. > > Thanks, > Oltmans http://lmgtfy.com/?q=python+html+to+pdf -- http://mail.python.org/mailman/listinfo/python-list
ssl, v23 client, v3 server...
In the ssl module docs (and in the tests) it says that if you have a client specifying PROTOCOL_SSLv23 (so it'll use v2 or v3) and a server specifying PROTOCOL_SSLv3 (so it'll only use v3) that you cannot connect between the two. Why doesn't this end up using SSL v3 for the communication? -- http://mail.python.org/mailman/listinfo/python-list
Re: Converting HTML to PDF using Python?
On 3/8/2010 12:51 PM, CM wrote: On Mar 8, 10:36 am, Oltmans wrote: Hi Python superstars, Guys, any ideas on how to convert HTML files to PDF files? Or as an alternative, how to convert HTML files to an image file(jpeg/png/etc)? Ideally, the converted PDF/Image file should like exactly like the way HTML file looks in the browser. How an HTML file looks in *a* (not *the*) browser depends on the browser, its settings, and window size. That is both a virtue and a reason for the invention of pdf format. I really have no idea about this so I will really appreciate all the help. Thanks in advance and kindly pardon my ignorance. Thanks, Oltmans http://lmgtfy.com/?q=python+html+to+pdf -- http://mail.python.org/mailman/listinfo/python-list
Re: Calculating very large exponents in python
On Mon, Mar 8, 2010 at 2:15 AM, Fahad Ahmad wrote:
> Thanks Geremy,
>
> That has been an absolute bump... GOD i cant sit on my chair, it has
> worked even on 512 bit number and with no time..
> superb i would say.
>
> lastly, i am using the code below to calculate Largest Prime factor of a
> number:
>
> print
> ('''==='''
> ''' CALCULATE HIGHEST PRIME
> FACTOR '''
>
> '''===''')
>
> #!/usr/bin/env python
> def highest_prime_factor(n):
> if isprime(n):
> return n
> for x in xrange(2,n ** 0.5 + 1):
> if not n % x:
> return highest_prime_factor(n/x)
> def isprime(n):
> for x in xrange(2,n ** 0.5 + 1):
> if not n % x:
> return False
> return True
> if __name__ == "__main__":
> import time
> start = time.time()
> print highest_prime_factor(1238162376372637826)
> print time.time() - start
>
> the code works with a bit of delay on the number : "1238162376372637826" but
> extending it to
> (109026109913291424366305511581086089650628117463925776754560048454991130443047109026109913291424366305511581086089650628117463925776754560048454991130443047)
> makes python go crazy. Is there any way just like above, i can have it
> calculated it in no time.
>
>
> thanks for the support.
If you're just looking for the largest prime factor I would suggest using
a fermat factorization attack. In the example you gave, it returns
nearly immediately.
Geremy Condra
--
http://mail.python.org/mailman/listinfo/python-list
Re: Calculating very large exponents in python
On Mon, Mar 8, 2010 at 2:05 PM, geremy condra wrote:
> On Mon, Mar 8, 2010 at 2:15 AM, Fahad Ahmad wrote:
>> Thanks Geremy,
>>
>> That has been an absolute bump... GOD i cant sit on my chair, it has
>> worked even on 512 bit number and with no time..
>> superb i would say.
>>
>> lastly, i am using the code below to calculate Largest Prime factor of a
>> number:
>>
>> print
>> ('''==='''
>> ''' CALCULATE HIGHEST PRIME
>> FACTOR '''
>>
>> '''===''')
>>
>> #!/usr/bin/env python
>> def highest_prime_factor(n):
>> if isprime(n):
>> return n
>> for x in xrange(2,n ** 0.5 + 1):
>> if not n % x:
>> return highest_prime_factor(n/x)
>> def isprime(n):
>> for x in xrange(2,n ** 0.5 + 1):
>> if not n % x:
>> return False
>> return True
>> if __name__ == "__main__":
>> import time
>> start = time.time()
>> print highest_prime_factor(1238162376372637826)
>> print time.time() - start
>>
>> the code works with a bit of delay on the number : "1238162376372637826" but
>> extending it to
>> (109026109913291424366305511581086089650628117463925776754560048454991130443047109026109913291424366305511581086089650628117463925776754560048454991130443047)
>> makes python go crazy. Is there any way just like above, i can have it
>> calculated it in no time.
>>
>>
>> thanks for the support.
>
> If you're just looking for the largest prime factor I would suggest using
> a fermat factorization attack. In the example you gave, it returns
> nearly immediately.
>
> Geremy Condra
>
Allow me to add a very important caveat to my previous statement:
a fermat factorization is primarily useful if you know that your number
is a large semiprime, such as an RSA modulus, which I assume you
are. Otherwise, make sure and test for primality.
Geremy Con
--
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Re: NoSQL Movement?
Xah Lee wrote: > For example, consider, if you are within world's top 100th user of > database in terms of database size, such as Google, then it may be > that the off-the-shelf tools may be limiting. But how many users > really have such massive size of data? You've totally missed the point. It isn't the size of the data you have today that matters, it's the size of data you could have in several years' time. Maybe today you've got 10 users each with 10 megabytes of data, but you're aspiring to become the next twitter/facebook or whatever. It's a bit late as you approach 100 million users (and a petabyte of data) to discover that your system isn't scalable: scalability needs to be built in from day one. -- http://mail.python.org/mailman/listinfo/python-list
Newbie question: python versions differ per user?
I'm on Mac OS X 10.5.8 and downloaded 2.6.4 Mac Installer Disk Image as/in(?) the sys admin user. For this user Pyhton 2.6.4 is now the current version. I want to use Python outside the sys asdmin user. However, all other users still use Python 2.5.1 (Apple delivered). The sys admin user looks in /Library/Frameworks/Python.framework/ Versions/2.6/lib/... The other users look in/System/Library/Frameworks/ Python.framework/Version/2.5/lib/... I could not find any questions on this matter, so am I the only one? Did I do something wrong? I assumed the paths for all users would be modified - too easy? -- http://mail.python.org/mailman/listinfo/python-list
Re: Calculating very large exponents in python
[Replying to Geremy's reply because the OP's post didn't show up in my newsreader.] On Mar 7, 8:40 pm, geremy condra wrote: > On Sun, Mar 7, 2010 at 1:55 PM, Fahad Ahmad wrote: > > Dear All, > > > i am writing my crytographic scheme in python, i am just a new user to it. > > I have written the complete code, the only point i am stuck it is that i am > > using 256 exponentiation which is normal in crytography but python just > > hangs on it. > > > g**x [where both g and x are 256 bit numbers , in decimal they are around > > 77] No library can solve this problem. If g and x are both 256-bit numbers then the result of g**x will have on the order of 10**79 bits, which matches estimates of the number of particles in the universe. I can only imagine that you actually want g**x % m for some m, in which case three-argument pow is your friend, as Geremy pointed out. -- Mark -- http://mail.python.org/mailman/listinfo/python-list
Re: negative "counts" in collections.Counter?
[Steven D'Aprano] > Thanks for the explanation Raymond. A few comments follow: You're welcome :-) > Would you consider a feature enhancement adding an additional method, > analogous to update(), to perform subtractions? I recognise that it's > easy to subclass and do it yourself, but there does seem to be some > demand for it, and it is an obvious feature given that Counter does > support negative counts. Will continue to mull it over. Instinct says that conflating two models can be worse for usability than just picking one of the models and excluding the other. If I had it to do over, there is a reasonable case that elementwise vector methods (__add__, __sub__, and __mul__) may have been a more useful choice than multiset methods (__add__, __sub__, __and__, __or__). That being said, the multiset approach was the one that was chosen. It was indicated for people who have experience with bags or multisets in other languages. It was also consistent with the naming of the class as tool for counting things (i.e. it handles counting numbers right out of the box). No explicit support is provided for negative values, but it isn't actively hindered either. For applications needing elementwise vector operations and signed arithmetic, arguably they should be using a more powerful toolset, perhaps supporting a full-range of elementwise binary and unary operations and a dotproduct() method. Someone should write that class and post it to the ASPN Cookbook to see if there is any uptake. > Personally, I think the behaviour of + and - would be far less surprising > if the class was called Multiset. Intuitively, one would expect counters > to be limited to ints, and to support negative counts when adding and > subtracting. In hindsight, do you think that Multiset would have been a > better name? The primary use case for Counter() is to count things (using the counting numbers). The term Multiset is more obscure and only applies to the four operations that eliminate non-positive results. So, I'm somewhat happy with the current name. FWIW, the notion of "what is surprising" often depends on the observer's background and on the problem they are currently trying to solve. If you need negative counts, then Counter.__sub__() is surprising. If your app has no notion of a negative count, then it isn't. The docs, examples, and docstrings are very clear about the behavior, so the "surprise" is really about wanting it to do something other than what it currently does ;-) Raymond -- http://mail.python.org/mailman/listinfo/python-list
Re: negative "counts" in collections.Counter?
On Mon, Mar 8, 2010 at 1:24 PM, Raymond Hettinger wrote:
> Instinct says that conflating two models can be worse for usability
> than just picking one of the models and excluding the other.
>
Toward that end, shouldn't Counter do one (and only one) of the follow?
1) Disallow non-positive counts (like a Multiset/Bag)
2) Allow them when subtracting
In other words, to avoid conflating two models the following two examples
should produce the same output:
>>> c = Counter({'red': 1})
>>> c['red'] -= 2
>>> c
Counter({'red': -1})
>>> c = Counter({'red': 1})
>>> c2 = Counter({'red': 2})
>>> c - c2
Counter()
--
Daniel Stutzbach, Ph.D.
President, Stutzbach Enterprises, LLC
--
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Re: write to remote ile
On 3/7/2010 9:53 PM, Martin P. Hellwig wrote:
On 03/08/10 02:51, monkeys paw wrote:
On 3/7/2010 9:20 PM, Martin P. Hellwig wrote:
On 03/08/10 02:10, monkeys paw wrote:
I can xfer a file from a remote server using:
import urllib2 as u
x=u.urlopen('http://tycho.usno.navy.mil/cgi-bin/timer.pl')
for line in x:
print line
How can i write a file to the remote server?
I tried:
x = u.url.open('http://joemoney.net/somefile.txt', 'w')
but that does not work
How do you normally (i.e. without python) put files on a remote server?
Using FTP, i'm really having a brain cramp here, but i'm new to python
We all been there, in some for or other ;-), anyway you might want to
have a look at this:
http://docs.python.org/library/ftplib.html
Tried this, the storlines doesn't work, everything else OK
from ftplib import FTP
ftp = FTP('joemoney.net')
ftp.login('secret','pw')
ftp.retrlines('LIST') # list directory contents
ftp.storlines('STOR', 'sf.xml') # Is this incorrect, it throws error>
File "ftp.py", line 5, in
ftp.storlines('STOR', 'sf.xml')
File "C:\Python26\lib\ftplib.py", line 470, in storlines
conn = self.transfercmd(cmd)
File "C:\Python26\lib\ftplib.py", line 356, in transfercmd
return self.ntransfercmd(cmd, rest)[0]
File "C:\Python26\lib\ftplib.py", line 327, in ntransfercmd
resp = self.sendcmd(cmd)
File "C:\Python26\lib\ftplib.py", line 243, in sendcmd
return self.getresp()
File "C:\Python26\lib\ftplib.py", line 218, in getresp
raise error_perm, resp
ftplib.error_perm: 501 No file name
The file exists in the same directory as ftp.py
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Re: negative "counts" in collections.Counter?
[Vlastimil Brom] > Thank you very much for the exhaustive explanation Raymond! You're welcome. > I am by far not able to follow all of the mathematical background, but > even for zero-truncating multiset, I would expect the truncation on > input rather than on output of some operations. I debated about this and opted for be-loose-in-receiving-and-strict-on- output. One thought is that use cases for multisets would have real multisets as inputs (no negative counts) and as outputs. The user controls the inputs, and the method only has a say in what its outputs are. Also, truncating input would complicate the mathematical definition of what is happening. Compare: r = a[x] - b[x] if r > 0: emit(r) vs. r = max(0, a[x]) - max(0, b[x]) if r > 0: emit(r) Also, the design parallels what is done in the decimal module where rounding is applied only to the results of operations, not to the inputs. > Probably a kind of negative_update() or some better named method will > be handy, like the one you supplied or simply the current module code > without the newcount > 0: ... condition. See my other post on this subject. There is no doubt that such a method would be handy for signed arithmetic. The question is whether conflating two different models hurts the API more than it helps. Right now, the Counter() class has no explicit support for negative values. It is designed around natural numbers and counting numbers. > Or would it be an option to > have a keyword argument like zero_truncate=False which would influence > this behaviour? Guido's thoughts on behavior flags is that they are usually a signal that you need two different classes. That is why itertools has ifilter() and ifilterfalse() or izip() and izip_longest() instead of having behavior flags. In this case, we have an indication that what you really want is a separate class supporting elementwise binary and unary operations on vectors (where the vector fields are accessed by a dictionary key instead of a positional value). > Additionally, were issubset and issuperset considered for this > interface (not sure whether symmetric_difference would be applicable)? If the need arises, these could be included. Right now, you can get the same result with: "if a - b: ..." FWIW, I never liked those two method names. Can't remember whether a.issubset(b) means "a is a subset of b" or "b issubset of a'. Raymond -- http://mail.python.org/mailman/listinfo/python-list
Re: Reverse engineering CRC?
Dave Angel wrote: If you know so little about the value, how do you even know it's a CRC ? Could it be a ones-complement sum, such as used in Ethernet? I'm going by the fact that the application reports a "CRC mismatch" when it's wrong. I can't be sure that what it calls a "CRC" is really a true CRC, but it's more than a simple sum, because changing one bit in the file results in a completely different value. Is the problem really worth it? Probably not -- it looks like fixing the problem I'm trying to fix by hand will be faster in the long run. I just thought it might turn out to be a solved problem and someone could point me to an algorithm for it, but it seems not. -- Greg -- http://mail.python.org/mailman/listinfo/python-list
Re: Import problem
Hi Steven,
Steven D'Aprano wrote:
> On Sat, 06 Mar 2010 03:53:53 -0800, Johny wrote:
>
> import sys
> sys.path.append('C:\\A')
> from A.B import bmodule
>> Traceback (most recent call last):
>> File "", line 1, in
>> ImportError: No module named A.B
>
> The current directory is irrelevant, except that it is automatically
> added to the PYTHONPATH. That's why you can import A.B when the current
> directory is C.
Minor currection:
It doesn't seem to be the current directory, but the directory, where
the script is located in, which is auto-appended to the pythonpath
Please see following example:
$ python -V
Python 2.6.4
$ mkdir A
$ touch A/__init__
$ # create A/blla.py an A/blo.py
$ cat A/bla.py
print "I am bla"
import A.blo
print "and I found blo",dir(A.blo)
$ cat A/blo.py
avar = 3
print "I am blo"
$ python A/bla.py
I am bla
Traceback (most recent call last):
File "A/bla.py", line 2, in
import A.blo
ImportError: No module named A.blo
However:
$ cat alternative_bla.py
import sys
sys.path.append(".")
print "I am bla"
import A.blo
print "and I found blo",dir(A.blo)
$ python A/alternativ_bla.py
I am bla
I am blo
and I found blo ['__builtins__', '__doc__', '__file__', '__name__',
'__package__', 'avar']
bye N
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Re: negative "counts" in collections.Counter?
Raymond Hettinger wrote: Instead the choice was to implement the four methods as multiset operations. As such, they need to correspond to regular set operations. Seems to me you're trying to make one data type do the work of two, and ending up with something inconsistent. I think you should be providing two types: one is a multiset, which disallows negative counts altogether; the other behaves like a sparse vector with appropriate arithmetic operations. -- Greg -- http://mail.python.org/mailman/listinfo/python-list
Re: negative "counts" in collections.Counter?
2010/3/8 Raymond Hettinger : ... [snip detailed explanations] >... > In this case, we have an indication that what you really want is > a separate class supporting elementwise binary and unary operations > on vectors (where the vector fields are accessed by a dictionary > key instead of a positional value). > > >> Additionally, were issubset and issuperset considered for this >> interface (not sure whether symmetric_difference would be applicable)? > > If the need arises, these could be included. Right now, you > can get the same result with: "if a - b: ..." > > FWIW, I never liked those two method names. Can't remember whether > a.issubset(b) means "a is a subset of b" or "b issubset of a'. > > > Raymond > -- > Thanks for the further remarks Raymond, initially I thought while investigating new features of python 3, this would be a case for replacing the "home made" solutions with the standard module functionality. Now I can see, it probably wouldn't be an appropriate decision in this case, as the expected usage of Counter with its native methods is different. As for the issubset, issuperset method names, I am glad, a far more skilled person has the same problem like me :-) In this case the operators appear to be clearer than the method names... regards, vbr -- http://mail.python.org/mailman/listinfo/python-list
Re: Import problem
Jean-Michel Pichavant wrote:
> Johny wrote:
>> I have this directory structure
>>
>> C:
>> \A
>> __init__.py
>> amodule.py
>>
>> \B
>> __init__.py
>> bmodule.py
>>
>>\D
>> __init__.py
>> dmodule.py
>>
>> and I want to import bmodule.py
>> C:\>cd \
>>
>> C:\>python
>> Python 2.5 (r25:51908, Sep 19 2006, 09:52:17) [MSC v.1310 32 bit
>> (Intel)] on win
>> 32
>> Type "help", "copyright", "credits" or "license" for more information.
>>
> from A.B import bmodule
>
>> I am bmodule
>> C:\>
>>
>> so far so good. Now I would like to import bmodule but if the current
>> directory is \D subdirectory.
>>
>> C:> cd \A\B\D
>> C:\A\B\D>
>> C:\A\B\D>python
>> Python 2.5 (r25:51908, Sep 19 2006, 09:52:17) [MSC v.1310 32 bit
>> (Intel)] on win
>> 32
>> Type "help", "copyright", "credits" or "license" for more information.
>>
> import sys
> sys.path.append('C:\\A')
> from A.B import bmodule
>
>> Traceback (most recent call last):
>> File "", line 1, in
>> ImportError: No module named A.B
>>
>> C:\>
>>
>> so I can not import a module from the parent directory? Or where did I
>> make an error?
>> Thanks for help
>>
>> L.
>>
> try
>
> import sys
> sys.path.append('C:\\')
> from A.B import bmodule
>
is there any 'automatic' way of finding the top level
directory?basically the 'top level directory is the first directory
going upwards, that doesn't contain a __init__.py file.
of course you could do this 'manually' by
doing:
# assume, that this module is A.amodule
import sys
import os
# I'd love to have a similiar automatic construct
if __name__ == "__main__":
level = 1 # or function locating how far to go up before
# finding a dir, whcih does not contain a __init__.py
mydir = os.path.split(__file__)[0]
topdir = os.path.join( mydir,*(("..",)*level))
abstop = os.path.abspath(topdir)
sys.path.append(abstop)
## now you can import with the normal module paths
import A.blo
print "and I found blo",dir(A.blo)
bye N
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Re: Import problem
Jean-Michel Pichavant wrote:
> Johny wrote:
>> I have this directory structure
>>
>> C:
>> \A
>> __init__.py
>> amodule.py
>>
>> \B
>> __init__.py
>> bmodule.py
>>
>>\D
>> __init__.py
>> dmodule.py
>>
>> and I want to import bmodule.py
>> C:\>cd \
>>
>> C:\>python
>> Python 2.5 (r25:51908, Sep 19 2006, 09:52:17) [MSC v.1310 32 bit
>> (Intel)] on win
>> 32
>> Type "help", "copyright", "credits" or "license" for more information.
>>
> from A.B import bmodule
>
>> I am bmodule
>> C:\>
>>
>> so far so good. Now I would like to import bmodule but if the current
>> directory is \D subdirectory.
>>
>> C:> cd \A\B\D
>> C:\A\B\D>
>> C:\A\B\D>python
>> Python 2.5 (r25:51908, Sep 19 2006, 09:52:17) [MSC v.1310 32 bit
>> (Intel)] on win
>> 32
>> Type "help", "copyright", "credits" or "license" for more information.
>>
> import sys
> sys.path.append('C:\\A')
> from A.B import bmodule
>
>> Traceback (most recent call last):
>> File "", line 1, in
>> ImportError: No module named A.B
>>
>> C:\>
>>
>> so I can not import a module from the parent directory? Or where did I
>> make an error?
>> Thanks for help
>>
>> L.
>>
> try
>
> import sys
> sys.path.append('C:\\')
> from A.B import bmodule
>
is there any 'automatic' way of finding the top level
directory?basically the 'top level directory is the first directory
going upwards, that doesn't contain a __init__.py file.
of course you could do this 'manually' by
doing:
# assume, that this module is A.amodule
import sys
import os
# I'd love to have a similiar automatic construct
if __name__ == "__main__":
level = 1 # or function locating how far to go up before
# finding a dir, whcih does not contain a __init__.py
mydir = os.path.split(__file__)[0]
topdir = os.path.join( mydir,*(("..",)*level))
abstop = os.path.abspath(topdir)
sys.path.append(abstop)
## now you can import with the normal module paths
import A.blo
print "and I found blo",dir(A.blo)
bye N
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Re: libc Sleep api performs a busy waiting
Hi Steve,
Steve Holden wrote:
> Mahesh wrote:
>> Hi,
>>
>> I am having a problem while using sleep function from libc , the
>> thread in which i am calling it is getting struck and not allowing
>> other threads to execute. Here is a simple code that i am trying to
>> exeute
>>
>> import threading
>> import time
>> import dl
>>
>>
>> def dummy1():
>> a=dl.open('/lib/libc.so.6')
>> print "in thread 1 Start"
>> a.call('sleep',2)
>> #time.sleep(2)
>> print "in thread 1 End"
>>
>> def dummy2():
>> print "in thread 2 Start"
>> time.sleep(1)
>> print "in thread 2 End"
>> newThread1=threading.Thread(None,dummy1)
>> newThread2=threading.Thread(None,dummy2)
>> newThread1.start()
>> newThread2.start()
>>
>> print "in main"
>>
>>
>>
>> The out put of this program is (In this case thread 1 even though i
>> am calling a sleep function its not allowing other threads to execute,
>> other threads execute only after the completion of first thread)
>>
>> in thread 1 Start
>> in thread 1 End
>> in thread 2 Start
>> in main
>> in thread 2 End
>>
>>
>> where as if i use time.sleep instead of a.call(sleep) the out put is
>> (which i guess is right behaviour, because it start the threads and
>> suspends them because the have sleep , and continue executing the main
>> thread)
>> in thread 1 Start
>> in thread 2 Start
>> in main
>> in thread 2 End
>> in thread 1 End
>>
>>
> Why not just use the time module's sleep function? Unlike the libc code
> it releases Python's GIL (global interpreter lock), thus allowing other
> threads to run.
>
I fully agree for the given example.
Especcially time.sleep allows even sub second sleeps.
Out of curiousity though:
Is there any way to perform a call(), that releases the GIL before
calling the function?
It would avoid writing a wrapper?
bye
N
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Re: What to do if anything bites.
Google Adsense wrote: > What to do if anything bites. > > Check our bites treatment at > > http://108ambulance.blogspot.com/2010/03/108-ambulance-home-page.html Pythons don't bite -- http://mail.python.org/mailman/listinfo/python-list
related lists mean value
Hi, I have two related lists: x = [1 ,2, 8, 5, 0, 7] y = ['a', 'a', 'b', 'c', 'c', 'c' ] what I need is a list representing the mean value of 'a', 'b' and 'c' while maintaining the number of items (len): w = [1.5, 1.5, 8, 4, 4, 4] I have looked at iter(tools) and next(), but that did not help me. I'm a bit stuck here, so your help is appreciated! thanks! Dimitri -- http://mail.python.org/mailman/listinfo/python-list
Re: negative "counts" in collections.Counter?
[Gregory Ewing] > I think you should be providing two types: one is a > multiset, which disallows negative counts altogether; > the other behaves like a sparse vector with appropriate > arithmetic operations. That is pretty close to what I said above: """ In this case, we have an indication that what you really want is a separate class supporting elementwise binary and unary operations on vectors (where the vector fields are accessed by a dictionary key instead of a positional value). """ The first and foremost goal of the class was to provide a simple counting capability along the lines of: class Counter(dict): def __init__(self, iterable=()): for elem in iterable: self[elem] += 1 def __missing__(self, key): return 0 Note, there is no "disallowing negatives" or even any insistence that the "counts" are actually numbers. In that respect, it was a consenting adults class from the start. It is short, simple, and fast. The other methods were mostly just "extras" to make the tool more useful. Each adds its own minimal restrictions: elements() requires integer counts most_common() requires that counts be orderable multiset operations are defined for non-negative values We could have kept this same design and wrapped every dictionary method so that it would raise an exception for any count that was not a positive integer. That would have slowed down the class, increased the code volume, and precluded some uses that are currently possible. IMO, that would not have been a win and it would not have helped the OP who was seeking a more vector-like tool for signed-number operations. Anyway, it is what it is. The tool is released and most users seem to be happy with what we have. Raymond -- http://mail.python.org/mailman/listinfo/python-list
Re: write to remote ile
monkeys paw wrote:
On 3/7/2010 9:53 PM, Martin P. Hellwig wrote:
On 03/08/10 02:51, monkeys paw wrote:
On 3/7/2010 9:20 PM, Martin P. Hellwig wrote:
On 03/08/10 02:10, monkeys paw wrote:
I can xfer a file from a remote server using:
import urllib2 as u
x=u.urlopen('http://tycho.usno.navy.mil/cgi-bin/timer.pl')
for line in x:
print line
How can i write a file to the remote server?
I tried:
x = u.url.open('http://joemoney.net/somefile.txt', 'w')
but that does not work
How do you normally (i.e. without python) put files on a remote server?
Using FTP, i'm really having a brain cramp here, but i'm new to python
We all been there, in some for or other ;-), anyway you might want to
have a look at this:
http://docs.python.org/library/ftplib.html
Tried this, the storlines doesn't work, everything else OK
from ftplib import FTP
ftp = FTP('joemoney.net')
ftp.login('secret','pw')
ftp.retrlines('LIST') # list directory contents
ftp.storlines('STOR', 'sf.xml') # Is this incorrect, it throws error>
The documentation says:
FTP.storlines(cmd, file, callback=None)
where 'cmd' is the FTP command, 'STOR sf.xml' ('sf.xl' is the path of
the file on the server) and 'file' is the open (local) source file.
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Re: Converting HTML to PDF using Python?
On 2010-03-08, Oltmans wrote:
> Guys, any ideas on how to convert HTML files to PDF files?
os.system("w3m -dump %s | a2ps -B --borders=no -o - | ps2pdf - %s" %
(infile,outfile))
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at PARENT or GUARDIAN?
gmail.com
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Re: related lists mean value
dimitri pater - serpia wrote: Hi, I have two related lists: x = [1 ,2, 8, 5, 0, 7] y = ['a', 'a', 'b', 'c', 'c', 'c' ] what I need is a list representing the mean value of 'a', 'b' and 'c' while maintaining the number of items (len): w = [1.5, 1.5, 8, 4, 4, 4] I have looked at iter(tools) and next(), but that did not help me. I'm a bit stuck here, so your help is appreciated! Try doing it in 2 passes. First pass: count the number of times each string occurs in 'y' and the total for each (zip/izip and defaultdict are useful for these). Second pass: create the result list containing the mean values. -- http://mail.python.org/mailman/listinfo/python-list
Re: related lists mean value
On Mon, Mar 8, 2010 at 2:34 PM, dimitri pater - serpia wrote: > Hi, > > I have two related lists: > x = [1 ,2, 8, 5, 0, 7] > y = ['a', 'a', 'b', 'c', 'c', 'c' ] > > what I need is a list representing the mean value of 'a', 'b' and 'c' > while maintaining the number of items (len): > w = [1.5, 1.5, 8, 4, 4, 4] > > I have looked at iter(tools) and next(), but that did not help me. I'm > a bit stuck here, so your help is appreciated! from __future__ import division def group(keys, values): #requires None not in keys groups = [] cur_key = None cur_vals = None for key, val in zip(keys, values): if key != cur_key: if cur_key is not None: groups.append((cur_key, cur_vals)) cur_vals = [val] cur_key = key else: cur_vals.append(val) groups.append((cur_key, cur_vals)) return groups def average(lst): return sum(lst) / len(lst) def process(x, y): result = [] for key, vals in group(y, x): avg = average(vals) for i in xrange(len(vals)): result.append(avg) return result x = [1 ,2, 8, 5, 0, 7] y = ['a', 'a', 'b', 'c', 'c', 'c' ] print process(x, y) #=> [1.5, 1.5, 8.0, 4.0, 4.0, 4.0] It could be tweaked to use itertools.groupby(), but it would probably be less efficient/clear. Cheers, Chris -- http://blog.rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Reverse engineering CRC?
Gregory Ewing wrote: Dave Angel wrote: If you know so little about the value, how do you even know it's a CRC ? Could it be a ones-complement sum, such as used in Ethernet? I'm going by the fact that the application reports a "CRC mismatch" when it's wrong. I can't be sure that what it calls a "CRC" is really a true CRC, but it's more than a simple sum, because changing one bit in the file results in a completely different value. Is the problem really worth it? Probably not -- it looks like fixing the problem I'm trying to fix by hand will be faster in the long run. I just thought it might turn out to be a solved problem and someone could point me to an algorithm for it, but it seems not. If you assume it's done in a single pass, and you know which byte is the end of the buffer, I'd think you could learn a lot by just tweaking that last byte. But I still think you'd want to automate your testing, presumably by some keystroke-stuffer. DaveA -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3.1.2 release candidate
On Mar 6, 4:13 pm, Benjamin Peterson wrote: > On behalf of the Python development team, I'm pleased to announce a release > candidate for the second bugfix release of the Python 3.1 series, Python > 3.1.2. > > This bug fix release fixes numerous issues found in 3.1.1. This release > candidate has been released to solicit testing and feedback over an possible > regressions from 3.1.1. Please consider testing it with your library or > application and reporting an bugs you encounter. This will help make the > final > 3.1.2 release, planned in 2 weeks time, all the more stable. > > The Python 3.1 version series focuses on the stabilization and optimization of > the features and changes that Python 3.0 introduced. For example, the new I/O > system has been rewritten in C for speed. File system APIs that use unicode > strings now handle paths with undecodable bytes in them. Other features > include > an ordered dictionary implementation, a condensed syntax for nested with > statements, and support for ttk Tile in Tkinter. For a more extensive list of > changes in 3.1, seehttp://doc.python.org/3.1/whatsnew/3.1.htmlor Misc/NEWS in > the Python distribution. > > To download Python 3.1.2rc1 visit: > > http://www.python.org/download/releases/3.1.2/ > > A list of changes in 3.1.2rc1 can be found here: > > http://svn.python.org/projects/python/tags/r312rc1/Misc/NEWS > > The 3.1 documentation can be found at: > > http://docs.python.org/3.1 > > Bugs can always be reported to: > > http://bugs.python.org Hey, it finally let me register. Turned out the e-mail to confirm registry was getting marked Spam. I pulled it out of the Spam box and completed the registration. Of course, the reason I needed to register is because IDLE will *still* not end a process properly in Windows. see issue 8093 > > Enjoy! > > -- > Benjamin Peterson > Release Manager > benjamin at python.org > (on behalf of the entire python-dev team and 3.1.2's contributors) -- http://mail.python.org/mailman/listinfo/python-list
Re: related lists mean value
thanks Chris and MRAB! Looks good, I'll try it out On Tue, Mar 9, 2010 at 12:22 AM, Chris Rebert wrote: > On Mon, Mar 8, 2010 at 2:34 PM, dimitri pater - serpia > wrote: >> Hi, >> >> I have two related lists: >> x = [1 ,2, 8, 5, 0, 7] >> y = ['a', 'a', 'b', 'c', 'c', 'c' ] >> >> what I need is a list representing the mean value of 'a', 'b' and 'c' >> while maintaining the number of items (len): >> w = [1.5, 1.5, 8, 4, 4, 4] >> >> I have looked at iter(tools) and next(), but that did not help me. I'm >> a bit stuck here, so your help is appreciated! > > from __future__ import division > > def group(keys, values): > #requires None not in keys > groups = [] > cur_key = None > cur_vals = None > for key, val in zip(keys, values): > if key != cur_key: > if cur_key is not None: > groups.append((cur_key, cur_vals)) > cur_vals = [val] > cur_key = key > else: > cur_vals.append(val) > groups.append((cur_key, cur_vals)) > return groups > > def average(lst): > return sum(lst) / len(lst) > > def process(x, y): > result = [] > for key, vals in group(y, x): > avg = average(vals) > for i in xrange(len(vals)): > result.append(avg) > return result > > x = [1 ,2, 8, 5, 0, 7] > y = ['a', 'a', 'b', 'c', 'c', 'c' ] > > print process(x, y) > #=> [1.5, 1.5, 8.0, 4.0, 4.0, 4.0] > > It could be tweaked to use itertools.groupby(), but it would probably > be less efficient/clear. > > Cheers, > Chris > -- > http://blog.rebertia.com > -- --- You can't have everything. Where would you put it? -- Steven Wright --- please visit www.serpia.org -- http://mail.python.org/mailman/listinfo/python-list
Re: Queue peek?
In article <58f61382-ac79-46fb-8612-a3c9fde29...@c16g2000yqd.googlegroups.com>, Veloz wrote: > >The "peek" parts comes in when the user comes back later to see if >their report has done. That is, in my page controller logic, I'd like >to look through the complete queue and see if the specific report has >been finished (I could tell by matching up the ID of the original >request to the ID in the completed queue). If there was an item in the >queue matching the ID, it would be removed. Here's the question: what happens when the user refreshes the "report done" page? The problem with the way you're doing it is that checking for report done is a one-shot operation. You probably want to use a database to cache this and have some kind of cache expiration. -- Aahz (a...@pythoncraft.com) <*> http://www.pythoncraft.com/ "Many customs in this life persist because they ease friction and promote productivity as a result of universal agreement, and whether they are precisely the optimal choices is much less important." --Henry Spencer -- http://mail.python.org/mailman/listinfo/python-list
Re: related lists mean value
On 3/8/2010 5:34 PM, dimitri pater - serpia wrote: Hi, I have two related lists: x = [1 ,2, 8, 5, 0, 7] y = ['a', 'a', 'b', 'c', 'c', 'c' ] what I need is a list representing the mean value of 'a', 'b' and 'c' while maintaining the number of items (len): w = [1.5, 1.5, 8, 4, 4, 4] I have looked at iter(tools) and next(), but that did not help me. I'm a bit stuck here, so your help is appreciated! Nobody expects object-orientation (or the Spanish Inquisition): #- from collections import defaultdict class Tally: def __init__(self, id=None): self.id = id self.total = 0 self.count = 0 x = [1 ,2, 8, 5, 0, 7] y = ['a', 'a', 'b', 'c', 'c', 'c'] # gather data tally_dict = defaultdict(Tally) for i in range(len(x)): obj = tally_dict[y[i]] obj.id = y[i] obj.total += x[i] obj.count += 1 # process data result_list = [] for key in sorted(tally_dict): obj = tally_dict[key] mean = 1.0 * obj.total / obj.count result_list.extend([mean] * obj.count) print result_list #- -John -- http://mail.python.org/mailman/listinfo/python-list
Re: related lists mean value
On 3/8/2010 9:39 PM, John Posner wrote: # gather data tally_dict = defaultdict(Tally) for i in range(len(x)): obj = tally_dict[y[i]] obj.id = y[i] <--- statement redundant, remove it obj.total += x[i] obj.count += 1 -John -- http://mail.python.org/mailman/listinfo/python-list
Re: related lists mean value
On 3/8/2010 9:43 PM, John Posner wrote: On 3/8/2010 9:39 PM, John Posner wrote: obj.id = y[i] <--- statement redundant, remove it Sorry for the thrashing! It's more correct to say that the Tally class doesn't require an "id" attribute at all. So the code becomes: #- from collections import defaultdict class Tally: def __init__(self): self.total = 0 self.count = 0 x = [1 ,2, 8, 5, 0, 7] y = ['a', 'a', 'b', 'c', 'c', 'c'] # gather data tally_dict = defaultdict(Tally) for i in range(len(x)): obj = tally_dict[y[i]] obj.total += x[i] obj.count += 1 # process data result_list = [] for key in sorted(tally_dict): obj = tally_dict[key] mean = 1.0 * obj.total / obj.count result_list.extend([mean] * obj.count) print result_list #- -John -- http://mail.python.org/mailman/listinfo/python-list
remove element with ElementTree
I have been using ElementTree to write an app, and would like to simply remove an element. But in ElementTree, you must know both the parent and the child element to do this. There is no getparent() function, so I am stuck if I only have an element. I am iterating over a table and getting all tags, checking their text, and conditionally deleting them: def RemoveElementWithText( topEl, subEl, text ): for el in topEl.getiterator( subEl ): if el.text = text: break else: el = None return el RemoveElementWithText( table, 'td', 'sometext' ) My table is like so: ... ... Is there any way to do this in ElementTree? I see lxml.etree does this nicely, but I want to use python's standard library. -- http://mail.python.org/mailman/listinfo/python-list
Re: libc Sleep api performs a busy waiting
Hi,
actually i have simplified my scenario a lot here ,
In my actual case , i have to call a C-api which blocks on c select , in a
separate thread.
my thread is getting struck in that api , and thus blocking all the other
threads.
Can you point to something which will help me call this blocking C-api call
without my thread getting struck.
Thanks
Mahesh
On Mon, Mar 8, 2010 at 6:03 PM, Steve Holden wrote:
> Mahesh wrote:
> > Hi,
> >
> > I am having a problem while using sleep function from libc , the
> > thread in which i am calling it is getting struck and not allowing
> > other threads to execute. Here is a simple code that i am trying to
> > exeute
> >
> > import threading
> > import time
> > import dl
> >
> >
> > def dummy1():
> > a=dl.open('/lib/libc.so.6')
> > print "in thread 1 Start"
> > a.call('sleep',2)
> > #time.sleep(2)
> > print "in thread 1 End"
> >
> > def dummy2():
> > print "in thread 2 Start"
> > time.sleep(1)
> > print "in thread 2 End"
> > newThread1=threading.Thread(None,dummy1)
> > newThread2=threading.Thread(None,dummy2)
> > newThread1.start()
> > newThread2.start()
> >
> > print "in main"
> >
> >
> >
> > The out put of this program is (In this case thread 1 even though i
> > am calling a sleep function its not allowing other threads to execute,
> > other threads execute only after the completion of first thread)
> >
> > in thread 1 Start
> > in thread 1 End
> > in thread 2 Start
> > in main
> > in thread 2 End
> >
> >
> > where as if i use time.sleep instead of a.call(sleep) the out put is
> > (which i guess is right behaviour, because it start the threads and
> > suspends them because the have sleep , and continue executing the main
> > thread)
> > in thread 1 Start
> > in thread 2 Start
> > in main
> > in thread 2 End
> > in thread 1 End
> >
> >
> Why not just use the time module's sleep function? Unlike the libc code
> it releases Python's GIL (global interpreter lock), thus allowing other
> threads to run.
>
> regards
> Steve
> --
> Steve Holden +1 571 484 6266 +1 800 494 3119
> PyCon is coming! Atlanta, Feb 2010 http://us.pycon.org/
> Holden Web LLC http://www.holdenweb.com/
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>
> --
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>
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imported var not being updated
Hello all: I have a project with many pyw files. One file holds a variable and a function that I find myself using across many other pyw files, so I called it helpers.pyw. The variable is "mostRecent", which is a string and is meant to hold a string so I know what the program most recently output; in all the other pyw files, every time the program outputs something, I include the line helpers.mostRecent=output where output is a string and helpers has been imported. The problem is that mostRecent does not seem to be updated at all, and I cannot figure out why. I declare it with empty quotes initially, but the program should keep updating it. Everytime I go to see what its value is, though, it is still apparently empty. Here is a basic sample: randomFile.pyw --- import helpers def something(): output="I am the most recently output string!" helpers.mostRecent=output #end def file2.pyw --- from helpers import mostRecent print(mostRecent) #prints nothing Any thoughts on what I am doing wrong? Thanks!! -- Have a great day, Alex (msg sent from GMail website) mehg...@gmail.com; http://www.facebook.com/mehgcap -- http://mail.python.org/mailman/listinfo/python-list
Re: imported var not being updated
Alex Hall wrote: Hello all: I have a project with many pyw files. One file holds a variable and a function that I find myself using across many other pyw files, so I called it helpers.pyw. The variable is "mostRecent", which is a string and is meant to hold a string so I know what the program most recently output; in all the other pyw files, every time the program outputs something, I include the line helpers.mostRecent=output where output is a string and helpers has been imported. The problem is that mostRecent does not seem to be updated at all, and I cannot figure out why. I declare it with empty quotes initially, but the program should keep updating it. Everytime I go to see what its value is, though, it is still apparently empty. Here is a basic sample: randomFile.pyw --- import helpers def something(): output="I am the most recently output string!" helpers.mostRecent=output #end def file2.pyw --- from helpers import mostRecent print(mostRecent) #prints nothing Any thoughts on what I am doing wrong? Thanks!! The form of import you are using from helpers import mostRecent makes a *new* binding to the value in the module that's doing the import. Rebinding the var in a different module does not affect this. It's similar to this: a = 'string' b = a a = 'another string' won't affect b's value. What you can do, is not make a separate binding, but reach into the helpers module to get the value there. Like this: import helpers print helpers.mostRecent That will work as you hope. Gary Herron -- http://mail.python.org/mailman/listinfo/python-list
Re: imported var not being updated
Thanks, it worked as expected. I guess I figured that Python would read my mind and realize that I wanted mostRecent to act globally for the program, imported as a copy or accessed in its own namespace (right term?) Oh well, the day computers can read thoughts like that is the day programmers are out of a job... Thanks again. On 3/8/10, Gary Herron wrote: > Alex Hall wrote: >> Hello all: >> I have a project with many pyw files. One file holds a variable and a >> function that I find myself using across many other pyw files, so I >> called it helpers.pyw. The variable is "mostRecent", which is a string >> and is meant to hold a string so I know what the program most recently >> output; in all the other pyw files, every time the program outputs >> something, I include the line >> helpers.mostRecent=output >> where output is a string and helpers has been imported. >> >> The problem is that mostRecent does not seem to be updated at all, and >> I cannot figure out why. I declare it with empty quotes initially, but >> the program should keep updating it. Everytime I go to see what its >> value is, though, it is still apparently empty. Here is a basic >> sample: >> >> randomFile.pyw >> --- >> import helpers >> >> def something(): >> output="I am the most recently output string!" >> helpers.mostRecent=output >> #end def >> >> file2.pyw >> --- >> from helpers import mostRecent >> >> print(mostRecent) #prints nothing >> >> Any thoughts on what I am doing wrong? Thanks!! >> > > The form of import you are using > from helpers import mostRecent > makes a *new* binding to the value in the module that's doing the > import. Rebinding the var in a different module does not affect this. > It's similar to this: > > a = 'string' > b = a > a = 'another string' > > won't affect b's value. > > What you can do, is not make a separate binding, but reach into the > helpers module to get the value there. Like this: > > import helpers > print helpers.mostRecent > > That will work as you hope. > > Gary Herron > > > -- > http://mail.python.org/mailman/listinfo/python-list > -- Have a great day, Alex (msg sent from GMail website) mehg...@gmail.com; http://www.facebook.com/mehgcap -- http://mail.python.org/mailman/listinfo/python-list
scipy sparse matrix question
I can't find any detailed information about scipy.sparse. My specific question: what does "for x in A" give me when A is a sparse matrix? It seems to yield all nonzero locations, but in what kind of form? Very specifically: how do I get the (i,j) coordinates and the value from x? Victor. -- Victor Eijkhout -- eijkhout at tacc utexas edu -- http://mail.python.org/mailman/listinfo/python-list
Re: Calculating very large exponents in python
[also replying to Geremy since the OP's message doesn't appear...]
On Mar 8, 11:05 am, geremy condra wrote:
> On Mon, Mar 8, 2010 at 2:15 AM, Fahad Ahmad wrote:
> > Thanks Geremy,
>
> > That has been an absolute bump... GOD i cant sit on my chair, it has
> > worked even on 512 bit number and with no time..
> > superb i would say.
>
> > lastly, i am using the code below to calculate Largest Prime factor of a
> > number:
>
> > print
> > ('''==='''
> > ''' CALCULATE HIGHEST PRIME
> > FACTOR '''
>
> > '''===''')
>
> > #!/usr/bin/env python
> > def highest_prime_factor(n):
> > if isprime(n):
> > return n
> > for x in xrange(2,n ** 0.5 + 1):
> > if not n % x:
> > return highest_prime_factor(n/x)
> > def isprime(n):
> > for x in xrange(2,n ** 0.5 + 1):
> > if not n % x:
> > return False
> > return True
> > if __name__ == "__main__":
> > import time
> > start = time.time()
> > print highest_prime_factor(1238162376372637826)
> > print time.time() - start
>
> > the code works with a bit of delay on the number : "1238162376372637826" but
> > extending it to
> > (109026109913291424366305511581086089650628117463925776754560048454991130443047109026109913291424366305511581086089650628117463925776754560048454991130443047)
> > makes python go crazy. Is there any way just like above, i can have it
> > calculated it in no time.
>
> > thanks for the support.
>
> If you're just looking for the largest prime factor I would suggest using
> a fermat factorization attack. In the example you gave, it returns
> nearly immediately.
>
> Geremy Condra- Hide quoted text -
>
> - Show quoted text -
For a Python-based solution, you might want to look at pyecm (http://
sourceforge.net/projects/pyecm/)
On a system with gmpy installed also, pyecm found the following
factors:
101, 521, 3121, 9901, 36479, 300623, 53397071018461,
1900381976777332243781
There still is a 98 digit unfactored composite:
60252507174568243758911151187828438446814447653986842279796823262165159406500174226172705680274911
Factoring this remaining composite using ECM may not be practical.
casevh
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How to detect C Function block using python
Hey All,
I'm new in this community. I am writing a static analyzer for validating C Code
using python and for that I'm looking for a python module/API that will detect
Function block of a given C-File. I know simple function can be detected using
push "{" and poping it if character "}" is found. This solution is actually
done already, I want a robust API that can do more then that like detecting
Function name parameters its return types etc.
Thanks!Faheem
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