Re: Can I use a conditional in a variable declaration?
[EMAIL PROTECTED] wrote:
> I've done this in Scheme, but I'm not sure I can in Python.
>
> I want the equivalent of this:
>
> if a == "yes":
>answer = "go ahead"
> else:
>answer = "stop"
>
> in this more compact form:
>
>
> a = (if a == "yes": "go ahead": "stop")
>
>
> is there such a form in Python? I tried playing around with lambda
> expressions, but I couldn't quite get it to work right.
I sometimes find it useful to do:
answers = {True: "go ahead", False: "stop"}
answer = answers[a == "yes"]
This is also sometimes useful when you want to alternate between two values.
values = {'a':'b', 'b':'a'} # define outside loop
while 1:
v = values[v] # alternate between 'a' and 'b'
...
There are limits to this, both the keys and the values need to be hashable.
Cheers,
Ron
--
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Re: ANNOUNCE: xlrd 0.5.2 -- extract data from Excel spreadsheets
On 19/03/2006 2:30 PM, Kent Johnson wrote: > John Machin wrote: > >> On 19/03/2006 8:31 AM, Kent Johnson wrote: >> >>> How does xlrd compare with pyexcelerator? At a glance they look >>> pretty similar. >>> >> >> I have an obvious bias, so I'll just leave you with a not-very-PC >> analogy to think about: >> >> Depending on the ambient light and the quantity of mead drunk in the >> hall, Helen of Troy and Grendel's mum might at a glance look pretty >> similar, too. Perhaps a more thorough investigation is needed. What >> about your requirements: a partner for the graduation ball, or someone >> to lift the truck off you when the jack collapses? > > > That didn't shed much light. I'm interested in your biased opinion, > certainly you must have had a reason to write a new package. > > I don't have current requirements for this, I'm curious. * It's not new. First public release was on 2005-05-15. When I started writing it, there was no pure-Python Excel reading facility available at all. Roman Kiseliov's pyExcelerator was first announced on c.l.py.ann on 2005-03-22 (write only) and later with an import facility on 2005-05-12. * I wrote it because I needed to get data out of Excel spreadsheets in a production environment. I had tried COM, ODBC, and manual save-as-CSV and all those approaches were unsatisfactory in terms of reliability and robustness. * Creating Excel files: xlrd doesn't do this. If you have Python 2.4, pyExcelerator is the best choice. The alternative is PyXLWriter which works with Python 2.2 onwards but is no longer maintained and writes only the older Excel 5.0 / Excel 95 file format (no Unicode support, limited to 16K rows). * Herewith the biased comparison: [I've CCed Roman on this & the previous posting, by the way] ** Python versions: xlrd 2.1 to 2.4, pyExcelerator 2.4 only ** Excel file versions: xlrd 3.0 onwards, pyExcelerator 5.0 onwards [I doubt there are many 3.0, 4S and 4W files hanging about but I had some Excel 4.0 files so I did it as a jeu d'esprit] ** Date support: Excel stores dates as real numbers of days sort-of since some variable date ... a long shocking story, read the xlrd docs. xlrd puts considerable effort into examining the formats used by number cells so that they can be classifed as date or not-date. It provides functions for converting between Excel date numbers and datetime tuples. ** Speed: On a 3.2GHz Intel P4 with 1 GB of RAM, xlrd loads a 128 Mb spreadsheet [yes sir, real live user data] in a little over a minute, while pyExcelerator takes a little over 3 minutes. Taking out half of that memory doesn't bother xlrd at all, but ... ** Memory footprint: pyExcelerator can use from 2.5 to 4 times as much memory as xlrd. ** Docs: xlrd has docs. Hoping that shed some light :-) Cheers, John -- http://mail.python.org/mailman/listinfo/python-list
python newb has problem with import statements
Hi Old hand at perl, giving python a try. Trying to get pymedia running on my winxp box. Have installed activestate python 2.4 and pymedia using precompiled installers. Problem is it SEEMS that the __init__.py is not getting run when I import a module. So, I have pymedia installed and it imports fine: >>> import pymedia >>> dir(pymedia) ['__builtins__', '__doc__', '__file__', '__name__'] >>> the init file looks like this: (docs and comments skipped) print "in pymedia" # added by me to see __all__= [ 'muxer', 'audio', 'video', 'removable' ] import muxer, audio, video, removable but I can't import submodules of pymedia: >>> import pymedia.sound Traceback (most recent call last): File "", line 1, in ? ImportError: No module named sound >>> if I do this >>> from pymedia import * >>> import pymedia.sound Traceback (most recent call last): File "", line 1, in ? ImportError: No module named sound >>> the weird thing is teh IDE (pythonwin) knows about the sub modules - it shows them in the auto-suggest thingy when I type "pymedia." so what's going on? do I have an install problem? (I did try removing and reinstalling, no avail) am I just misunderstanding how this should work? all helpful stuff much appreciated Daniel -- http://mail.python.org/mailman/listinfo/python-list
Re: python newb has problem with import statements
[EMAIL PROTECTED] wrote: > the init file looks like this: > > (docs and comments skipped) > > print "in pymedia" # added by me to see > __all__= [ 'muxer', 'audio', 'video', 'removable' ] > import muxer, audio, video, removable > > but I can't import submodules of pymedia: The file with the contents given above is clearly not the one that is imported here, > >>> import pymedia > >>> dir(pymedia) > ['__builtins__', '__doc__', '__file__', '__name__'] as __all__, muxer, audio etc. are missing. Maybe you have created a test script 'pymedia.py' in the working directory? You can check what file you are dealing with by entering >>> pymedia.__file__ If that is 'whatever/site-packages/pymedia/__init__.pyc' I'm guessing wrong. Otherwise removing that file (probably 'pymedia.pyc') and the corresponding source (pymedia.py) should fix your problem. Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: Can I use a conditional in a variable declaration?
Jeffrey Schwab wrote: > [EMAIL PROTECTED] wrote: > >> I want the equivalent of this: >> >> if a == "yes": >>answer = "go ahead" >> else: >>answer = "stop" >> >> in this more compact form: >> >> a = (if a == "yes": "go ahead": "stop") >> >> is there such a form in Python? I tried playing around with lambda >> expressions, but I couldn't quite get it to work right. > > Rather than lambda, this merits a named function. You only have to > define it once. > > def mux(s, t, f): > if s: > return t > return f But be aware that this is not a complete replacement for a syntactic construct. With that function, Python will always evaluate all three arguments, in contrast to the and/or-form or the Python 2.5 conditional. You can show this with test = mux(False, 1/0, 1) and test = False and 1/0 or 1 Georg -- http://mail.python.org/mailman/listinfo/python-list
Re: Is Jython development active?
[EMAIL PROTECTED] wrote: > Don't seem to see much progress in getting out a new version of Jython. > The last beta was out in March 2005. When will a final release be made? Not sure, but I've been checking jython-dev and jython-checkins once every few days (yes, I am *that* interested in Jython). Seems that Frank Wierzbicki and Otmar Humbel have been quite busy in the past 2 months! :) Keep your fingers crossed. I hope Frank will finish the new website and get back to Jython itself soon. (Not to discount anything that Frank has been doing, but IMHO the old website was just fine.) For myself, I've been looking into Jython code whenever I have the time, I hope I can help one day and contribute instead of just checking those two lists like 4 times a week :) -- http://mail.python.org/mailman/listinfo/python-list
Re: Python compiler
"robert" <[EMAIL PROTECTED]> schreef in bericht news:[EMAIL PROTECTED] > Rc wrote: >> "DaveM" <[EMAIL PROTECTED]> schreef in bericht >> news:[EMAIL PROTECTED] >> >>>On Thu, 16 Mar 2006 13:34:14 +0100, "Méta-MCI" >>><[EMAIL PROTECTED]> wrote: >>> >>> Après, vous pourrez aussi fréquenter le newsgroup : fr.comp.lang.python qui a l'avantage d'être en français. >>> >>>But perhaps he's a Flemish speaker - are you trying to start a riot? >>> >>>DaveM >> >> Yes,I'm a Flemish speaker, I have been to school in the evening >> to study Englisch and also now for the last year I'm study French. >> To improve my English it's maybe good to work with English >> newsgroupes.I'm not looking for a riot,because I don't understand >> the word.By the way, in case to learn Python,they told me it's >> the most esay language to start. >> But ,my question is when I start Python it is a Dos Window >> that opened.I think it is not possible on a XP computer? >> Or am I wrong. >> Thanks by advances >> Rc > > install Pythonwin (pywin32) for a GUI Thank for the answers.But I have looked to several sites where can I download that install Pythonwin(pywin32) for a GUI. There are so much ,I don't no exactly, which site or which download. Thanks by advance Rc -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 2.5 Schedule
Yes, it's very annoying to see VC8 warnings on perfectly legal C constructs (AFAIK even sprinf is now considered "unsafe", MS wants everybody to use sprintf_s). But the optimisation capacities of VC8 are really great. Maybe someone can measure the speedup? P.S. there's an "_CRT_SECURE_NO_DEPRECATE" flag that eliminates most of this kind of warnings. Also, #pragma 's can be used (although this isn't nice at all). P.P.S. are there any experiments with compiling CPython with Intel's compiler? -- http://mail.python.org/mailman/listinfo/python-list
Re: ANNOUNCE: xlrd 0.5.2 -- extract data from Excel spreadsheets
John Machin wrote: > On 19/03/2006 2:30 PM, Kent Johnson wrote: >>That didn't shed much light. I'm interested in your biased opinion, >>certainly you must have had a reason to write a new package. > > * It's not new. First public release was on 2005-05-15. When I started > writing it, there was no pure-Python Excel reading facility available at > all. Roman Kiseliov's pyExcelerator was first announced on c.l.py.ann > on 2005-03-22 (write only) and later with an import facility on 2005-05-12. Ah, my mistake, sorry. I didn't recall hearing about xlrd before and jumped to the conclusion that it was new, though your OP is very clear that this is an update release. > * Herewith the biased comparison: Thank you! Kent -- http://mail.python.org/mailman/listinfo/python-list
Re: python library for web discussions
reddit is written with webpy (webpy.org), maybe you should give it a try? -- http://mail.python.org/mailman/listinfo/python-list
Re: How do I use the subprocess module with mswindows?
Darren Dale <[EMAIL PROTECTED]> wrote: > import subprocess > process = subprocess.Popen(['dir'], stderr=subprocess.STDOUT, > stdout=subprocess.PIPE) > stat = process.wait() > print process.stdout.read() You have already gotten the answer to why 'dir' doesn't work for you, but there is a bug hiding in that code that you might not notice in simple tests. You are waiting for your subprocess to complete without reading away what it prints. That will quickly fill the buffer available in the pipe between you and the subprocess, and the subprocess will block. Try calling Popen() with something that prints more data, like ['find', '/', '-print'] on a Unix box, and you will notice that problem. What you should do is: output = process.stdout.read() stat = process.wait() print output Or, you could use the .communicate() method on the Popen object instead of .stdout.read(). If you find yourself juggling several subprocesses running in parallel, producing and/or consuming data "incrementally", or just trying to handle both sending input to and reading output from a single subprocess without deadlocking, you may be helped by using my asyncproc module, which you can download from http://www.lysator.liu.se/~bellman/download/asyncproc.py I suspect that it only works on Unix, though. -- Thomas Bellman, Lysator Computer Club, Linköping University, Sweden "Beware of bugs in the above code; I have! bellman @ lysator.liu.se only proved it correct, not tried it." ! Make Love -- Nicht Wahr! -- http://mail.python.org/mailman/listinfo/python-list
Re: interrupting pythonD with ^C
John Savage wrote: > I'm finding that many times when I inadvertently code an endless loop > in pythonD code, on MSDOS, execution cannot be interrupted by ctrl-C > and I am forced to reboot and this is rapidly loses its novelty. > > Do users of pythonD have a coding technique, or a library file to include, > to endow a program with keyboard interrupt-ability? > > Endless loops arise when I forget to increment a loop index, or code > incorrectly the end condition test, or indent wrongly, etc. Well, you could try programming more carefully :-) Alternatively, try CTRL/Break. That seems to interrupt even when a program is waiting on a network socket, which CTRL/C doesn't seem to. Note, however, that this terminates the process without raising KeyboardInterrupt. regards Steve -- Steve Holden +44 150 684 7255 +1 800 494 3119 Holden Web LLC/Ltd www.holdenweb.com Love me, love my blog holdenweb.blogspot.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Can I use a conditional in a variable declaration?
[EMAIL PROTECTED] wrote:
>I've done this in Scheme, but I'm not sure I can in Python.
>
>I want the equivalent of this:
>
>if a == "yes":
> answer = "go ahead"
>else:
> answer = "stop"
>
>in this more compact form:
>
>
>a = (if a == "yes": "go ahead": "stop")
>
>
>is there such a form in Python? I tried playing around with lambda
>expressions, but I couldn't quite get it to work right.
>
>
>
How about:
a = ["stop","go ahead"][a == "yes"]
This works because:
>>> int("yes" == "yes")
1
>>> int("yes" == "no")
0
Taking into account all the previous comments - both the literal list
elements are evaluated; there is no short-cirtuiting here. If they're
just literals, it's no problem, but if they're (possibly
compute-intensive) function calls, it would matter. I find the list
evaluation easier to parse than the and/or equation, and in instances
where that would be necessary, I will use the longhand if ... else ...
structure for readability.
hth,
-andy
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Re: python library for web discussions
Gregory Petrosyan wrote: > reddit is written with webpy (webpy.org), maybe you should give it a > try? I'm looking for a library that provides commenting on items in a similar way to reddit/digg/slashdot. I would rather not write all that code from scratch. I don't think web.py comes with that functionality, although of course, some free package may provide it on top of web.py. Amir -- http://mail.python.org/mailman/listinfo/python-list
Re: Getting .NET SDK to work with Python 2.4.2
Dave wrote: > yea i have .net 1.1, but not the sdk. do i need the 1.1 SDK too? I think so. The .Net 1.1 runtime (i.e. - not the SDK) is missing the support files necessary for compiling programs. Gotta love those huge downloads. I thought the Java SDK's were big :-)~ -- http://mail.python.org/mailman/listinfo/python-list
Counting number of each item in a list.
I have a list a little something like this: StringA StringC StringB StringA StringC StringD StringA ... etc. Basically I was wondering if there was an easy way to return how many of each string are in the list, something like this: StringA - 3 StringB - 1 StringC - 2 StringD - 1 I suppose that the easiest way to do that is to convert it to a 2 dimensional array? Is there any easy way? Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: Getting .NET SDK to work with Python 2.4.2
Dave wrote: > So i go to the cmd and go to the directory and type > "python setup.py build" (Will have to install after) and it comes up > with this(after everything else runs smoothly): > running build_ext > error: The .NET SDK needs to be installed before building extensions > for python. The error message is misleading. It is not the SDK that you need, but Visual Studio 7.1. Alternatively, you can try building the extension with the GNU mingw32 compiler. Regards, Martin -- http://mail.python.org/mailman/listinfo/python-list
Want to re-pack() a Frame displaying a collection
List, I'd like to do the following with Tkinter's Frame() object: 1. Display a collection of pack()-able objects. Easy. Done. I hold the objects in a dictionary, mostly so that the owning program can refer to them uniformly. 2. Whenever the collection is added to or deleted from, re-pack() the owning object. Will this happen automatically simply whenever I add or delete from the object's __dict__, or do I need to add to __setattr__ and __delattr__ to detect when the user has added or removed an object? Thanks Not Quite Related: I'm doing a lot of displaying of (Label, Entry) pairs so I've another subclass of Frame() that simplifies that action for me. These are items from a collection that's created at runtime where the labels aren't known in advance. Right now, I'm raising an exception if grid() or place() is called on the object. Eventually, what I'd like to do is flesh out the grid() and place() methods so that the Label and Entry are placed in what I think are sensible default positions reletive to the desired placement. With grid(), how do I determine my current column and row in the case when grid() is invoked without arguments? With place() . .pretty much the same song. I need to determine my position so that I can Do The Right Thing (or at least the expected thing). Thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: Counting number of each item in a list.
"sophie_newbie" <[EMAIL PROTECTED]> writes: > I suppose that the easiest way to do that is to convert it to a 2 > dimensional array? Is there any easy way? Use a hash table. Untested: h = 0 for x in your_list: h[x] = h.get(x, 0) + 1 You can then use something like sorted(h.items()) to get a sorted list of those counts. -- http://mail.python.org/mailman/listinfo/python-list
Re: Getting .NET SDK to work with Python 2.4.2
Well i don't have the whole visual studio. I don't have 7 either, I have 8. I have VB and VC++ Express. If there is no way to download VS7, could someone point me to directions on how to build the extensions with mingw32? -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 2.5 Schedule
Hi, what I would like to see in (www.python.org) is Windows installation package (*.msi) compiled with option "--enable-unicode=ucs4". See http://www.xml.com/pub/a/2005/06/15/py-xml.html -pekka- -- http://mail.python.org/mailman/listinfo/python-list
Re: Counting number of each item in a list.
sophie_newbie a écrit : > I have a list a little something like this: > > StringA > StringC > StringB > StringA > StringC > StringD > StringA > ... > etc. > > Basically I was wondering if there was an easy way to return how many > of each string are in the list, something like this: > > StringA - 3 > StringB - 1 > StringC - 2 > StringD - 1 There is. str_list = ['StringA', 'StringC', 'StringB', 'StringA', 'StringC', 'StringD', 'StringA' ] str_counts = dict((s, str_list.count(s) for s in set(str_list)) -- http://mail.python.org/mailman/listinfo/python-list
Re: Counting number of each item in a list.
Hey Bruno, I got an invalid syntax error when i tried using your "str_counts = dict((s, str_list.count(s) for s in set(str_list))" bit of code? Maybe there is a missing bracket or comma? Or maybe I need to import something. Thanks so much for your help. -- http://mail.python.org/mailman/listinfo/python-list
Re: How to run SimpleHTTPServer on IronPython on Mono
[EMAIL PROTECTED] wrote: > Paul Boddie wrote: > > [1] http://lists.debian.org/debian-legal/2005/08/msg00089.html > > Do you realize *I* was the person asking for clarification of the license > on debian-legal mailing list? Yes. And I thereby deduce that you also believe that having Debian approval would mean a lot for IronPython's acceptance, since the Debian people are regarded as being the most stringent with respect to Free Software-compatible licensing in distributions. > > If IronPython users consider themselves to be > > part of the wider Python community, is it a good thing that they're > > reliant on Microsoft to keep that community from fragmenting? > > I quite don't get what you are trying to say here. This was about how CPython can get away from other implementations by adding new features. As we've seen with Jython, if there's relatively little community interest in keeping other Python implementations up-to-date, and if there's no sponsor with the manpower on hand to do the work, then everyone in the CPython camp is busy using such new features in their code, while everyone else is busy wondering if they'll ever see such new features. Microsoft seem to be committed to delivering IronPython, and perhaps if they lose interest the community will step in and do the work, but in such a situation I feel that the whole Python community (users of CPython *and* other implementations combined) will suffer "fragmentation" as CPython speeds ahead and IronPython lags behind just as Jython has done. Sure, choosing Jython or IronPython is usually a trade-off between wanting some of the nice Python libraries and wanting access respectively to Java and CLR libraries, and perhaps many people using these implementations don't consider themselves as part of (or primary members of) the wider Python community; if so, it could be said that the Python "brand" is somewhat diminished already, since people may be willing to accept slightly more limited variants of the language, using implementation-specific libraries where standard library facilities exist, and generally writing an increasingly divergent dialect of the language. Personally, I think that having more implementations is a good thing for the language, mostly because it leads to new and interesting technical opportunities, but more engagement and support from the community "standards legislators" will definitely become necessary over time to avoid confusion about what is and is not "proper Python", especially if more people don't arrive at Python via CPython. Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: Counting number of each item in a list.
Hi Paul,
Ur bit of code works, thanks so much, just for anyone reading this use
'h = {}' instead of h = 0.
Thanks
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Problems redirecting STDOUT (NOT sys.stdout) to a pipe.
Hello All, I am trying to capture some printf's from a C function called by python. I have tried to following: STDOUT = 1# stdout fd (re, we) = os.pipe()# Create re / write handlers dup2(we, STDOUT)# override system's stdout, should dup first and restore later.. call_my_hello_world() # if stdout is not overriden will print hello world on console screen x = os.read(re, 11) sadly, x = '' after the code is executed. help ? :-) Thanks, Elad. -- http://mail.python.org/mailman/listinfo/python-list
Re: Getting .NET SDK to work with Python 2.4.2
"Dave" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] | Well i don't have the whole visual studio. I don't have 7 either, I | have 8. I have VB and VC++ Express. If there is no way to download VS7, | could someone point me to directions on how to build the extensions | with mingw32? | I used the free MS Visual C++ Toolkit 2003 successfully to compile extenstions before I had access to VS. There's a how to here: http://www.vrplumber.com/programming/mstoolkit/ Regards, Vincent Wehren -- http://mail.python.org/mailman/listinfo/python-list
Re: Have you ever considered of mousing ambidextrously?
In article <[EMAIL PROTECTED]>, John Salerno <[EMAIL PROTECTED]> wrote: > Roy Smith wrote: > > In article <[EMAIL PROTECTED]>, > > Scott David Daniels <[EMAIL PROTECTED]> wrote: > > > >> Roy Smith wrote: > >>> I never understood why people switch mouse buttons. I'm left handed, so > >>> I > >>> put the mouse on the left side of my keyboard. It never occurred to me > >>> to > >>> flip the buttons around. > >> Well, I switch 'em because the "forefinger is primary" is ingrained. > > > > I do both buttons with my forefinger. It just seems like the normal thing > > to do. > > How do you manage that? Do you keep your finger hovered over the mouse? > It seems like quite an effort to move it back and forth between the two > buttons, unless you have a smaller mouse. Mostly, I've got both hands on the keyboard. I don't spend a lot of time holding the mouse. -- http://mail.python.org/mailman/listinfo/python-list
Re: Counting number of each item in a list.
sophie_newbie wrote: > Hey Bruno, > > I got an invalid syntax error when i tried using your "str_counts = > dict((s, str_list.count(s) for s in set(str_list))" bit of code? Maybe > there is a missing bracket or comma? Or maybe I need to import > something. It should be str_counts = dict((s, str_list.count(s)) for s in set(str_list)) or for Python < 2.4 str_counts = dict([(s, str_list.count(s)) for s in set(str_list)]) Note that this solution iterates str_list once for each element of str_list - the call to count traverses the entire list to create the count. I expect Paul Rubin's solution will be dramatically faster for large lists as it only iterates str_list once. Kent -- http://mail.python.org/mailman/listinfo/python-list
Re: Getting .NET SDK to work with Python 2.4.2
So this means that I have to download .NET 1.1 SDK. Visual Studio 8 comes with msvcrt.lib, but im assuming it's the wrong version. -- http://mail.python.org/mailman/listinfo/python-list
C-API: A beginner's problem
I recently started learning C since I want to be able to write Python
extension modules. In fact, there is no need for it, but I simply want
to try something new ...
I tried to implement the bubblesort algorithm in C and to use it in
python; bubblesort.c compiles fine, but whenever I want to import the
modul and call the function I get a segmentation fault. This is what the
code looks like:
static PyObject *py_bubblesort(PyObject *self, PyObject *args) {
PyObject *seq = NULL, *item, *newseq = NULL;
int seqlen, i;
if(!PyArg_ParseTuple(args, "O", &seq)) {
return NULL;
}
seq = PySequence_Fast(seq, "argument must be iterable");
if(!seq) {
return NULL;
}
seqlen = PySequence_Fast_GET_SIZE(seq);
int list[seqlen];
for (i = 0; i <= seqlen; i++) {
item = PySequence_Fast_GET_ITEM(seq, i);
list[i] = item;
}
bubblesort(list, seqlen);
newseq = PyList_New(seqlen);
if(!newseq) {
return NULL;
}
for(i = 0; i < seqlen; i++) {
PyList_SetItem(newseq, i, list[i]);
}
return newseq;
bubblesort(int list[], int seqlen) is doing the actual job and it is
working.
What did I do wrong? As I am quite new to C, I probably made many
mistakes, so please feel free to correct me.
Cheers,
Fabian
--
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Re: C-API: A beginner's problem
Fabian Steiner wrote:
> What did I do wrong? As I am quite new to C, I probably made many
> mistakes, so please feel free to correct me.
The following line:
> for (i = 0; i <= seqlen; i++) {
Should be "for (i = 0; i < seqlen; i++) {". Otherwise the last
assignment will be out of bounds and probably corrupts heap.
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Re: Python 2.5 Schedule
Gregory Petrosyan wrote: > P.P.S. are there any experiments with compiling CPython with Intel's > compiler? Yup, the (older) Intel compiler was quite effective for 2,2 and 2.3 (at least), and I think at least one distro was built with it. -- -Scott David Daniels [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
Re: python newb has problem with import statements
that was indeed the problem. Thanks! -- http://mail.python.org/mailman/listinfo/python-list
Re: C-API: A beginner's problem
Heikki Salo wrote:
> Fabian Steiner wrote:
>> What did I do wrong? As I am quite new to C, I probably made many
>> mistakes, so please feel free to correct me.
>
> The following line:
>
> > for (i = 0; i <= seqlen; i++) {
>
> Should be "for (i = 0; i < seqlen; i++) {". Otherwise the last
> assignment will be out of bounds and probably corrupts heap.
And closer look tells that the code should not even compile. Is the code
cut & pasted directly? Line "list[i] = item;" tries to assign a pointer
to an int-array, which should not compile. There are other similar oddities.
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Re: Python 2.5 Schedule
Pekka Niiranen wrote: > what I would like to see in (www.python.org) is > Windows installation package (*.msi) > compiled with option "--enable-unicode=ucs4". > See http://www.xml.com/pub/a/2005/06/15/py-xml.html Just enabling that option is not enough: the resulting binary likely crashes. In addition to changing the type of Py_UNICODE, you also need change all calls to Microsoft API that expects UCS-2 (i.e. all *W API). Contributions are welcome. Regards, Martin -- http://mail.python.org/mailman/listinfo/python-list
Re: ANNOUNCE: xlrd 0.5.2 -- extract data from Excel spreadsheets
Kent Johnson wrote: > John Machin wrote: >> * Herewith the biased comparison: > > Thank you! Thank you (John) as well. I realize you are a bit reluctant to toot your own horn, but it is just this kind of biased comparison that let's us know whether to investigate further. It also helps that you mention what pyExcelerator is good at. -- -Scott David Daniels [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
Re: Computing correlations with SciPy
Tested it and it works like a charm! Thank you very much for fixing this. Not knowing what an SVN is, I simply copied the code into the appropriate library files and it works perfectly well. May I suggest a simple enhancement: modify corrcoef so that if it is fed two 1 dimensional arrays, it returns a scalar. cov does something similar for covariances: if you feed it just one vector, it returns a scalar, and if you feed it two, it returns the covariance matrix i.e: >>> x = [1, 2, 3, 4, 5] >>> z = [5, 4, 3, 2, 1] >>> scipy.cov(x,z) array([[ 2.5, -2.5], [-2.5, 2.5]]) >>> scipy.cov(x) 2.5 I suspect that the majority of users use corrcoef to obtain point estimates of the covariance of two vectors, and relatively few will estimate a covariance matrix, as this method tends not to be robust to the presence of noise and/or errors in the data. Thomas Philips -- http://mail.python.org/mailman/listinfo/python-list
Initializing a list of lists
I want to create a list of lists, each of which is identical, but which can be modified independently i.e: >>>x = [ [0], [0], [0] ] >>> x[0].append(1) >>> x [[0, 1], [0], [0]] The above construct works if I have only few items, but if I have many, I'd prefer to write >>> N =3 >>> x =N*[[0]] >>> x [[0], [0], [0]] If I now try extending the lists indepently, I cannot, as they all point to the same list object >>> x[0].append(1) >>> x [[0, 1], [0, 1], [0, 1]] Is there a simple way to create a list of independent lists? Thanks in advance Thomas Philips -- http://mail.python.org/mailman/listinfo/python-list
Re: C-API: A beginner's problem
Heikki Salo wrote: > > And closer look tells that the code should not even compile. Is the > code cut & pasted directly? Line "list[i] = item;" tries to assign a > pointer to an int-array, which should not compile. There are other > similar oddities. ... such as the declaration of list at a point in the code which is not permitted in C, and using a non constant value for the length (which is also not allowed). -- http://mail.python.org/mailman/listinfo/python-list
Relative paths in mod_python
I was wondering if I could use relative paths in a mod_python script. At the moment I am defining a constant string "/path/to/dir/where/script/resides". The problem with this is that when I move the script including files I use to get metadata I have to change this variable. The same problem occurs when I distribute the script; the person using it will first have to modify it, which is not what I want. Is it possible that a mod_python script has as current working directory the directory where the script resides? At the moment os.getcwd() returns '/'. -- http://mail.python.org/mailman/listinfo/python-list
Re: Initializing a list of lists
> The above construct works if I have only few items, but if I have many, > I'd prefer to write > N =3 x =N*[[0]] x > > [[0], [0], [0]] > > If I now try extending the lists indepently, I cannot, as they all > point to the same list object > x[0].append(1) x > > [[0, 1], [0, 1], [0, 1]] > > Is there a simple way to create a list of independent lists? My first thought would be >>> N = 10 >>> x = [[0] for _ in range(N)] >>> x[0].append(1) >>> x [[0, 1], [0], [0], [0], [0], [0], [0], [0], [0], [0]] HTH, -tkc -- http://mail.python.org/mailman/listinfo/python-list
Re: Initializing a list of lists
Ciao, [EMAIL PROTECTED] Che stavi dicendo? > Is there a simple way to create a list of independent lists? N=3 x=[[0] for e in range(N)] -- Up da 1 giorno, 3 ore, 43 minuti e 10 secondi -- http://mail.python.org/mailman/listinfo/python-list
Re: Can I use a conditional in a variable declaration?
Georg Brandl wrote: > Jeffrey Schwab wrote: >> [EMAIL PROTECTED] wrote: >> >>> I want the equivalent of this: >>> >>> if a == "yes": >>>answer = "go ahead" >>> else: >>>answer = "stop" >>> >> def mux(s, t, f): >> if s: >> return t >> return f > > But be aware that this is not a complete replacement for a syntactic > construct. With that function, Python will always evaluate all three > arguments, in contrast to the and/or-form or the Python 2.5 conditional. Absolutely true, and I should have mentioned it. In languages that allow ?: syntax, I rarely rely on its short-circuit effect, but it certainly is a significant difference. -- http://mail.python.org/mailman/listinfo/python-list
Re: C-API: A beginner's problem
Duncan Booth wrote: > Heikki Salo wrote: > > > > > And closer look tells that the code should not even compile. Is the > > code cut & pasted directly? Line "list[i] = item;" tries to assign a > > pointer to an int-array, which should not compile. There are other > > similar oddities. > > ... such as the declaration of list at a point in the code which is not > permitted in C, and using a non constant value for the length (which is > also not allowed). They are allowed in C99, according to GCC's manual. -- http://mail.python.org/mailman/listinfo/python-list
Problem with Install wxPython on Solaris10 x86
I want to install wxPython 2.6 on Solaris10 x86. I have passed "make install", and want to execute python setup.py install. but i got some problems. first i run "python setup.py install",and i got the following: unable to execute cc: No such file or directory error: command 'cc' failed with exit status 1 so, it seams no cc in my solaris10. I have installed SunStudio11, and there is a cc at /opt/SUNWspro/bin this cc is the suncc,so i added "/opt/SUNWspro/bin" to my PATH but i still got problem : cc: Warning: option -3 passed to ld cc: No input file specified, no output generated error: command 'cc' failed with exit status 1 I also tried to replace "cc" with "gcc", and still failed. Anyone installed wxPython successfully on solaris10? ps: sorry for my poor english. -- http://mail.python.org/mailman/listinfo/python-list
Unpythonic? Impossible??
Assume having this class hierarchy: (in principle and without details) class A(object): class B1(A): class B2(A): class C1(A1): class C2(A1): class C3(B1): class C4(B2): each of those classes have an initializer __init__(self, data): and an overloaded __new__(cls, data): is it then possible to have this call: obj = A(data) return an instance of that particular class (e.g. class C3) in the hierarchy that - as decided by the __new__ functions - is the 'correct' one? A.__new__ could select between A, B1 and B2, while B1.__new__ could choose from B1, C3 and C4. I know how to use a class factory - and could work around using such a mechanism. However I am interested to know if I could let the classes do the work by themselves. /BJ -- http://mail.python.org/mailman/listinfo/python-list
Re: C-API: A beginner's problem
Nick Smallbone wrote: > Duncan Booth wrote: >> Heikki Salo wrote: >> >> > >> > And closer look tells that the code should not even compile. Is the >> > code cut & pasted directly? Line "list[i] = item;" tries to assign a >> > pointer to an int-array, which should not compile. There are other >> > similar oddities. >> >> ... such as the declaration of list at a point in the code which is not >> permitted in C, and using a non constant value for the length (which is >> also not allowed). > > They are allowed in C99, according to GCC's manual. > > Which just shows how long it is since I wrote any C. -- http://mail.python.org/mailman/listinfo/python-list
Re: Unpythonic? Impossible??
BrJohan wrote: > Assume having this class hierarchy: (in principle and without details) > class A(object): > class B1(A): > class B2(A): > ... > each of those classes have an initializer __init__(self, data): and an > overloaded __new__(cls, data): > > is it then possible to have this call: > obj = A(data) > return an instance of that particular class (e.g. class C3) in the > hierarchy that - as decided by the __new__ functions - is the 'correct' one? > > A.__new__ could select between A, B1 and B2, while B1.__new__ could choose > from B1, C3 and C4. > > I know how to use a class factory - and could work around using such a > mechanism. However I am interested to know if I could let the classes do the > work by themselves. Yes, it can be done. Yes, it is unclear (and hence UnPythonic). The class factory _is_ the straightforward way to do this. The following is the workaround (if you have to maintain A(...)): class A(object): def __new__(class_, *args, **kwargs): if class_ is A: if want_a_B1(*args, **kwargs): return B1(*args, **kwargs) elif want_a_B2(*args, **kwargs): return B2(*args, **kwargs) return object.__new__(class_) # Use *a,... except for object class B1(A): def __new__(class_, *args, **kwargs): if class_ is B1: if want_a_B1(*args, **kwargs): return B1(*args, **kwargs) elif want_a_B2(*args, **kwargs): return B2(*args, **kwargs) return super(B1, class_).__new__(class_, *args, **kwargs) --Scott David Daniels [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
Rate of Flow in a Black Box
Hi all. Here's the problem: I've got a black box and a bunch of particles in an environment. The particles go into the black box, follow a path, and pop out the end after some processing. They are processed first-in-first-out, like a queue. Inside the black box is a physical layout that can be thought of as a series of pipes or a lineup at an airport checkin. The interior layout can change at runtime (ie, a pipe can be rerouted or the airline employee can move one of the fabric cordons). But it is a black box and we don't know the layout at any given time. The particles are either Red or Green. Green particles report their positions to the server every x seconds. Red particles do not. So the only information we can get out of the black box is the positions of the green particles as they make their way through the pipes. Furthermore, there is some errorFactor when a particle reports its position to the server. So if two lengths of pipe are close together, a Green particle could report that it is in a position that would actually be in the other length of pipe. The only knowledge the server has is the reported positions of the Green particles over time, and a rectangle where the black box is located. When the particles get to the end of the pipe, they are processed in batches of 4-8 and then spit out of the black box. The position where they are spit out is far away from the rest of the black box, so we know for sure when a particle is out. I need to estimate how long it is going to take a new particle entering the black box to get processed. First I'll just ask if this is a well known problem or could be shoehorned into a well known problem. And additionally - is there some existing Python library / code that solves it. I've got 3 (mediocre) candidate solutions, but it seems like something that should be already solved. -sjbrown -- http://mail.python.org/mailman/listinfo/python-list
Re: Counting number of each item in a list.
sophie_newbie a écrit : > Hey Bruno, > > I got an invalid syntax error when i tried using your "str_counts = > dict((s, str_list.count(s) for s in set(str_list))" bit of code? Maybe > there is a missing bracket or comma? Yes, sorry, see Kent's post for the correction. > Or maybe I need to import > something. Nope, unless you're running python < 2.4 -- http://mail.python.org/mailman/listinfo/python-list
Re: Counting number of each item in a list.
With CPython this is probably the faster version, the version with
list.count() has to be used only if you are sure to always have a short
input list, because it's O(n^2):
str_list = ['StringA', 'StringC', 'StringB',
'StringA', 'StringC', 'StringD',
'StringA' ]
str_counts = {}
for s in str_list:
if s in str_counts:
str_counts[s] += 1
else:
str_counts[s] = 1
Bye,
bearophile
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Re: Counting number of each item in a list.
Kent Johnson a écrit : > sophie_newbie wrote: > >> Hey Bruno, >> >> I got an invalid syntax error when i tried using your "str_counts = >> dict((s, str_list.count(s) for s in set(str_list))" bit of code? Maybe >> there is a missing bracket or comma? Or maybe I need to import >> something. > > > It should be > str_counts = dict((s, str_list.count(s)) for s in set(str_list)) Of course, my bad :( > or for Python < 2.4 from sets import Set as set > str_counts = dict([(s, str_list.count(s)) for s in set(str_list)]) > > Note that this solution iterates str_list once for each element of > str_list once for each *distinct* element or str_list (it iterates over the set created from str_list). > - the call to count traverses the entire list to create the > count. I expect Paul Rubin's solution will be dramatically faster for > large lists as it only iterates str_list once. Yeps. But I would benchmark it before choosing one or the other solution. -- http://mail.python.org/mailman/listinfo/python-list
[ann] markup.py - HTML/XML generator
Just in case the thought of not having a millionth implementation of a HTML/XML generator for Python makes the world as we know it a miserable place, well then your suffering might be over soon since exactly the one millionth implementation is out. You can download markup.py from http://markup.sourceforget.net/ Oh, and the code is in the public domain. -- http://mail.python.org/mailman/listinfo/python-list
Re: C-API: A beginner's problem
Heikki Salo wrote:
> Heikki Salo wrote:
>> Fabian Steiner wrote:
>>> What did I do wrong? As I am quite new to C, I probably made many
>>> mistakes, so please feel free to correct me.
>>
>> The following line:
>>
>> > for (i = 0; i <= seqlen; i++) {
>>
>> Should be "for (i = 0; i < seqlen; i++) {". Otherwise the last
>> assignment will be out of bounds and probably corrupts heap.
>
> And closer look tells that the code should not even compile. Is the code
> cut & pasted directly? Line "list[i] = item;" tries to assign a pointer
> to an int-array, which should not compile. There are other similar
> oddities.
Okay, thank you (and the others) for these hints. As you see, I am quite
new to C and I just wrote these lines by using parts I have found in the
newsgroup. Unfortunately, the Python C-API documentation / tutorial
won't help me since it is quite difficult to understand because of the
lack of basics.
What do I have to change in order to make the code work?
Thank you very much in advance!
Cheers,
Fabian
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Re: Python equivalent of Perl-ISAPI?
What Roger says and also: http://pyisapie.sourceforge.net/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Unpythonic? Impossible??
Em Dom, 2006-03-19 às 08:54 -0800, Scott David Daniels escreveu: > class A(object): > def __new__(class_, *args, **kwargs): > if class_ is A: > if want_a_B1(*args, **kwargs): > return B1(*args, **kwargs) > elif want_a_B2(*args, **kwargs): > return B2(*args, **kwargs) > return object.__new__(class_) # Use *a,... except for object > > class B1(A): > def __new__(class_, *args, **kwargs): > if class_ is B1: > if want_a_B1(*args, **kwargs): > return B1(*args, **kwargs) > elif want_a_B2(*args, **kwargs): > return B2(*args, **kwargs) > return super(B1, class_).__new__(class_, *args, **kwargs) Why you have that if on B1.__new__? B1 will be created only by A.__new__, which already did a check. -- Felipe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Unpythonic? Impossible??
"Scott David Daniels" <[EMAIL PROTECTED]> skrev i meddelandet news:[EMAIL PROTECTED] > BrJohan wrote: ... >> is it then possible to have this call: >> obj = A(data) >> return an instance of that particular class (e.g. class C3) in the >> hierarchy that - as decided by the __new__ functions - is the 'correct' >> one? >> >> A.__new__ could select between A, B1 and B2, while B1.__new__ could >> choose from B1, C3 and C4. >> >> I know how to use a class factory - and could work around using such a >> mechanism. However I am interested to know if I could let the classes do >> the work by themselves. > > Yes, it can be done. Yes, it is unclear (and hence UnPythonic). > The class factory _is_ the straightforward way to do this. The > following is the workaround (if you have to maintain A(...)): > > > class A(object): > def __new__(class_, *args, **kwargs): > if class_ is A: > if want_a_B1(*args, **kwargs): > return B1(*args, **kwargs) > elif want_a_B2(*args, **kwargs): > return B2(*args, **kwargs) > return object.__new__(class_) # Use *a,... except for object > > class B1(A): > def __new__(class_, *args, **kwargs): > if class_ is B1: > if want_a_B1(*args, **kwargs): > return B1(*args, **kwargs) > elif want_a_B2(*args, **kwargs): > return B2(*args, **kwargs) > return super(B1, class_).__new__(class_, *args, **kwargs) > > > --Scott David Daniels > [EMAIL PROTECTED] Agreed that the class factory method most often (maybe always) is the best one. For certain reasons, and in this particular case, I prefer the UnPythonic way. Sometimes it's good to have "more than one way to do it". It was the "return object.__new__(class_) " that I did not came to think of myself, that did it. Thank you for yor helpfulness. BrJohan -- http://mail.python.org/mailman/listinfo/python-list
Re: Relative paths in mod_python
Ivo van der Sangen wrote: > I was wondering if I could use relative paths in a mod_python script. At > the moment I am defining a constant string > "/path/to/dir/where/script/resides". > [snip] You can use Python's built-in __file__ variable. It is set to the absolute location of your script. You can then use one of the built-in functions in the `os' module (I forgot which) to extract the directory your script resides. Jochem. -- E-mail address encrypted using ROT13. -- http://mail.python.org/mailman/listinfo/python-list
Re: Server applications - avoiding sleep
You can make it a service, which has an advantage, that it survives logouts. SOME PROGRAMMING IS REQIURED. If I need something running the "fast and dirty" way, I run a regular python application as window application (start pythonw.exe). As a way o communication (start, stop, pause) I use tray. If you nee an example of such a program, I can send one. "rodmc" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] >I have written a small server application (for Windows) which handles > sending and receiving information from an instant messaging client and > a database. This server needs to run 24/7, however it stops when the > computer screen is locked. > > I assume there is a way to make it run in the background 24/7 but how > do I go about doing this? > > At present the application runs from within a wxPython GUI, however > this is only used to start and stop it. It could be entire faceless and > the GUI only used to execute it. > > Best, > > rod > -- http://mail.python.org/mailman/listinfo/python-list
Re: Unpythonic? Impossible??
Felipe Almeida Lessa wrote: > Em Dom, 2006-03-19 às 08:54 -0800, Scott David Daniels escreveu: >> class A(object): >> def __new__(class_, *args, **kwargs): >> if class_ is A: >> if want_a_B1(*args, **kwargs): >> return B1(*args, **kwargs) >> elif want_a_B2(*args, **kwargs): >> return B2(*args, **kwargs) >> return object.__new__(class_) # Use *a,... except for object >> >> class B1(A): >> def __new__(class_, *args, **kwargs): >> if class_ is B1: >> if want_a_B1(*args, **kwargs): >> return B1(*args, **kwargs) >> elif want_a_B2(*args, **kwargs): >> return B2(*args, **kwargs) >> return super(B1, class_).__new__(class_, *args, **kwargs) > > Why you have that if on B1.__new__? B1 will be created only by > A.__new__, which already did a check. Of course your are right. It needs to be more like: class B1(A): def __new__(class_, *args, **kwargs): if class_ is B1: if want_a_C1(*args, **kwargs): return C1(*args, **kwargs) elif want_a_C2(*args, **kwargs): return C1(*args, **kwargs) return super(B1, class_).__new__(class_, *args, **kwargs) --Scott David Daniels [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
Re: Writing web bots in python
On 2006-03-18, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > Hello, > I hav a question..How do I write a webbot that logs onto some website, > fills text into a textbox and submit that form, Sorry I am a novice in > python, apparently I have to use urllib, but I hav a few queries on > this, What happens when there are more input interfaces..does urllib > make somekind of a template when it does so..need more info on > this..links and tutorilas would be appreciated..thanx Not strictly Python related, but if you use Firefox, get the "Tamper Data" extension for it. This lets you see exactly what Firefox is submitting in the formdata, and what the urls are of the cgi scripts etc. I usually invoke a program called curl from python with os.popen, but this twill someone has suggested looks interesting. -- http://mail.python.org/mailman/listinfo/python-list
Re: Counting number of each item in a list.
Bruno Desthuilliers a écrit :
> Kent Johnson a écrit :
>
>> sophie_newbie wrote:
>>
>>> Hey Bruno,
>>>
>>> I got an invalid syntax error when i tried using your "str_counts =
>>> dict((s, str_list.count(s) for s in set(str_list))" bit of code? Maybe
>>> there is a missing bracket or comma? Or maybe I need to import
>>> something.
>>
>>
>>
>> It should be
>> str_counts = dict((s, str_list.count(s)) for s in set(str_list))
>
>
> Of course, my bad :(
>
>> or for Python < 2.4
>
>
> from sets import Set as set
>
>> str_counts = dict([(s, str_list.count(s)) for s in set(str_list)])
>>
>> Note that this solution iterates str_list once for each element of
>> str_list
>
>
> once for each *distinct* element or str_list (it iterates over the set
> created from str_list).
>
>> - the call to count traverses the entire list to create the count. I
>> expect Paul Rubin's solution will be dramatically faster for large
>> lists as it only iterates str_list once.
>
> Yeps. But I would benchmark it before choosing one or the other solution.
And of course, I was right. My solution seems to be faster than Paul's
one (but slower than bearophile's), be it on small, medium or large lists.
nb: A is mine, B is Paul's and C is bearophile's, and the number after
is the size of the list...
A100 (1 times): 1.5801050663
B100 (1 times): 1.87287902832
C100 (1 times): 0.991976976395
A1 (100 times): 1.083589077
B1 (100 times): 1.30713891983
C1 (100 times): 0.988032817841
A100 (10 times): 10.5345788002
B100 (10 times): 13.094493866
C100 (10 times): 9.67438292503
source:
def countA(lst):
return dict((s, lst.count(s)) for s in set(lst))
def countB(lst):
counts = {}
for s in lst:
counts[s] = counts.get(s, 0)+1
return counts
def countC(lst):
counts = {}
for s in lst:
if s in counts:
counts[s] += 1
else:
counts[s] = 1
return counts
def mklst(ln):
from random import choice
items = ['abc', 'def', 'ghi', 'jkl', 'mno',
'pqr', 'stu', 'vwx', 'yz']
return [choice(items) for i in range(ln)]
lst100 = mklst(100)
lst1 = mklst(1)
lst100 = mklst(100)
def run():
from timeit import Timer
timers = [
('A100',
Timer('countA(lst100)',
'from __main__ import countA, lst100'),
1),
('B100',
Timer('countB(lst100)',
'from __main__ import countB, lst100'),
1),
('C100',
Timer('countC(lst100)',
'from __main__ import countC, lst100'),
1),
('A1',
Timer('countA(lst1)',
'from __main__ import countA, lst1'),
100),
('B1',
Timer('countB(lst1)',
'from __main__ import countB, lst1'),
100),
('C1',
Timer('countC(lst1)',
'from __main__ import countC, lst1'),
100),
('A100',
Timer('countA(lst100)',
'from __main__ import countA, lst100'),
10),
('B100',
Timer('countB(lst100)',
'from __main__ import countB, lst100'),
10),
('C100',
Timer('countC(lst100)',
'from __main__ import countC, lst100'),
10),
]
for name, timer, repeat in timers:
print "%s (%s times): %s" % (name,
repeat,
timer.timeit(repeat))
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Re: Relative paths in mod_python
Ivo van der Sangen a écrit : > I was wondering if I could use relative paths in a mod_python script. At > the moment I am defining a constant string > "/path/to/dir/where/script/resides". The problem with this is that when > I move the script including files I use to get metadata I have to change > this variable. The same problem occurs when I distribute the script; the > person using it will first have to modify it, which is not what I want. Is > it possible that a mod_python script has as current working directory > the directory where the script resides? At the moment os.getcwd() > returns '/'. You could set this constant in the apache conf as a PythonOption. And/Or you could post this question to mod_python's mailing list !-) -- http://mail.python.org/mailman/listinfo/python-list
Re: python cgi permision error
Sorry accidently replying using my other google account [EMAIL PROTECTED] wrote: > > > > assuming you are running this python script the standard cgi way and not > > through modpython or fastcgi. > yes I'm running it in standard cgi way coz my provider only allow me > that way. And it's really just simple script. Sorry for the dumb question, I know modpython but what do you mean by fast cgi > > > > > try debugging this way. > > > > execute the python script from command line as the web user. > > > > make sure your python script prints the standard > > > > """Content-type: text/html > > > > """ > Yess I've done that. I have also run it on windows machine and it work. It seem my apache from SuSE 10.0 had some weird error permision that I don't understand when running cgi. I'm also had that kinda error if I running other cgi on perl or binary cgi :( -- http://mail.python.org/mailman/listinfo/python-list
Re: message box halts prgram flow
[EMAIL PROTECTED] a écrit :
> HI
>
> I am creating a tkinter app.
>
> example
>
> tkMessageBox.showinfo("Window Text", "A short message")
> print "blah"
>
> The execution of the application halts when the message box is
> displayed until the user clicks OK, then "blah is printed.
Yeps, this is pretty much what anyone would expect from a sensible GUI
toolkit.
>
> However I want the program to display message box and continue on to
> print blah without waiting for user response.
What's your use case ?
> Any suggestions on how to go about this?
Either use a non-modal window instead of a modal dialog box or use
different threads.
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Re: Counting number of each item in a list.
Bruno Desthuilliers <[EMAIL PROTECTED]> writes: > And of course, I was right. My solution seems to be faster than Paul's > one (but slower than bearophile's), be it on small, medium or large > lists. > > nb: A is mine, B is Paul's and C is bearophile's, and the number after > is the size of the list... Interesting. I wonder if you could try it with a much larger number of distinct values in the list. -- http://mail.python.org/mailman/listinfo/python-list
Re: Counting number of each item in a list.
Bruno Desthuilliers wrote: > And of course, I was right. My solution seems to be faster than Paul's > one (but slower than bearophile's), be it on small, medium or large lists. Your version is only fast on lists with a very small number of unique elements. changing mklist to have items = range(64) instead of the 9 item list and re-timing you will get "better" results: A100 (1 times): 7.63829684258 B100 (1 times): 1.34028482437 C100 (1 times): 0.812223911285 A1 (100 times): 9.78499102592 B1 (100 times): 1.26520299911 C1 (100 times): 0.857560873032 A100 (10 times): 87.6713900566 B100 (10 times): 12.7302949429 C100 (10 times): 8.35931396484 -- - Justin -- http://mail.python.org/mailman/listinfo/python-list
Re: remove a directory with special chars
andy wrote:
> Is there a special reason you want to use Python to do this? The Linux
> command shell would probably do exactly the same job (you can specify
> backslash-escaped characters at the command-line)...
>
> anyway to do it in python:
>
> import os
> os.remove("/path/to/the/file/.\177\177")
>
> Note that under Linux, hidden files start with a "." - that's what makes
> them hidden.
>
> By the way, "\177" (decimal 79) is a letter "O"... I suspect you meant
> "\011" (decimal 9) which is backspace...
Actually, \177 is DEL, while the letter O is \117.
Definitely confusing, but then octal sucks anyway.
-Peter
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[ANN] PyGNUGK v3.50 is out
Hi there, I'm pleased to announce PyGNUGK v3.50 which is available under the terms of the GNU GPL from : http://cortex.unice.fr/~jerome/pygnugk/ PyGNUGK is a Python library which allows full control over one or more instances of the GNU GateKeeper (http://www.gnugk.org) from any Python program. PyGNUGK comes with : - The Python library. - Sample code : - A sample program which can be run : - From the command line : it prints plain text, HTML or XML reports about the list of registered endpoints and ongoing calls. - As a CGI script : When there's no user authentication, it allows the same reports as from the command line. With user authentication (i.e. Apache's .htaccess files) the HTML report contains links which can disconnect active calls or endpoints and unregister endpoints. - A test program which tests all available functions of the gatekeeper. - A Zope Product : For now it can produce HTML and XML reports, but more features will be added later. NB : the sample programs can be used directly, however for advanced needs you have to use the library. A screenshot of the CGI script taken from an earlier release is available from : http://cortex.unice.fr/~jerome/pygnugk/screenshot.png Comments are very much welcome. bye Jerome Alet -- http://mail.python.org/mailman/listinfo/python-list
Re: Counting number of each item in a list.
Paul Rubin a écrit : > Bruno Desthuilliers <[EMAIL PROTECTED]> writes: > >>And of course, I was right. My solution seems to be faster than Paul's >>one (but slower than bearophile's), be it on small, medium or large >>lists. >> >>nb: A is mine, B is Paul's and C is bearophile's, and the number after >>is the size of the list... > > > Interesting. I wonder if you could try it with a much larger number > of distinct values in the list. Please do, this could be interesting... -- http://mail.python.org/mailman/listinfo/python-list
Re: Counting number of each item in a list.
Justin Azoff a écrit : > Bruno Desthuilliers wrote: > >>And of course, I was right. My solution seems to be faster than Paul's >>one (but slower than bearophile's), be it on small, medium or large lists. > > > Your version is only fast on lists with a very small number of unique > elements. > > changing mklist to have > items = range(64) instead of the 9 item list and re-timing you will get > "better" results: > > A100 (1 times): 7.63829684258 > B100 (1 times): 1.34028482437 > C100 (1 times): 0.812223911285 > > A1 (100 times): 9.78499102592 > B1 (100 times): 1.26520299911 > C1 (100 times): 0.857560873032 > > A100 (10 times): 87.6713900566 > B100 (10 times): 12.7302949429 > C100 (10 times): 8.35931396484 > Lol !-) So much for my benchmarking skills... -- http://mail.python.org/mailman/listinfo/python-list
Re: Counting number of each item in a list.
Justin Azoff a écrit : > Bruno Desthuilliers wrote: > >> My solution seems to be faster than Paul's >>one (but slower than bearophile's), be it on small, medium or large lists. > > > Your version is only fast on lists with a very small number of unique > elements. > > changing mklist to have > items = range(64) instead of the 9 item list and re-timing you will get > "better" results: > > A100 (1 times): 7.63829684258 > B100 (1 times): 1.34028482437 > C100 (1 times): 0.812223911285 > > A1 (100 times): 9.78499102592 > B1 (100 times): 1.26520299911 > C1 (100 times): 0.857560873032 > > A100 (10 times): 87.6713900566 > B100 (10 times): 12.7302949429 > C100 (10 times): 8.35931396484 > > Lol ! So much for my benchmarking skills :-/ -- http://mail.python.org/mailman/listinfo/python-list
whats your favourite object relational mapper?
With so many object relational mappers out there, I wonder which one is the preferred tool among the Pythonists... is there a favourite? Sqlobject, PyDO, SQLAlchemy, dejavu, etc... -- http://mail.python.org/mailman/listinfo/python-list
Re: Xah's Edu Corner: What is Expressiveness in a Computer Language
What is Expressiveness in a Computer Language Xah Lee, 200502, 200603. In languages human or computer, there's a notion of expressiveness. English for example, is very expressive in manifestation, witness all the poetry and implications and allusions and connotations and dictions. There are a myriad ways to say one thing, fuzzy and warm and all. But when we look at what things it can say, its power of expression with respect to meaning, or its efficiency or precision, we find natural languages incapable. These can be seen thru several means. A sure way is thru logic, linguistics, and or what's called Philosophy of Languages. One can also glean directly the incapacity and inadequacy of natural languages by studying the artificial language lojban, where one realizes, not only are natural languages incapable in precision and lacking in efficiency, but simply a huge number of things are near impossible to express thru them. One thing commonly misunderstood in computing industry is the notion of expressiveness. If a language has a vocabulary of (smile, laugh, grin, giggle, chuckle, guffaw, cackle), then that language will not be as expressive, as a language with just (severe, slight, laugh, cry). The former is “expressive” in terms of nuance, where the latter is expressive with respect to meaning. Similarly, in computer languages, expressiveness is significant with respect to semantics, not syntactical variation. These two contrasting ideas can be easily seen thru Perl versus Python languages, and as one specific example of their text pattern matching capabilities. Perl is a language of syntactical variegations. Lisp on the other hand, is a example of austere syntax uniformity, yet its efficiency and power in expression, with respect to semantics, showcases Perl's poverty in specification. Example: String Patterns in Regex In Perl, the facilities for finding and replacing a text pattern is this construct “$myText =~ s/myPattern/replStr/”. In Python, it is “re.sub( myPattern, replStr, myText , myCount)”, where the replacement string repStr can be a function, and a max number of replacement myCount can be specified. If there is a match, and if replStr is given a function myFunc instead, then a special regex match object is feed to myFunc and it can return different strings based on how the pattern is matched. This is a instance where the language is more expressive. In Python's regex facilities, there are several other flexibilities not present in Perl. For example, its regex pattern can be frozen as a compiled object and moved about. And, when a there is a match, Python returns a special object that contains all information about the regex, such as the original pattern, the number of matches, the set of matched strings and so on, and this object can be passed around, or have information extracted. These facilities are absent in Perl. In this case, the flexibilities and facilities of Python's texual patterns matching's capabilities a instance of superior expressiveness to Perl's. For more about Python's Regex machinery, see the Re-written Python Regex Documentation at: http://xahlee.org/python_re-write/lib/module-re.html Example: Range, and Computation with Fractions In Perl, there's a range construct “(a..b)” that returns a list of numbers from a to b. However, this construct cannot generate a list with regular intervals such as (1, 3, 5, 7, 9). Nor would it generate decreasing lists such as (4, 3, 2, 1) when a > b. In Python, its range function range(a,b,c) returns a range of numbers from a to b with steps c. For example, range(3,-5, -2) returns [3, 2, 1, -1, -3]. The arguments can be negative, however, they all must be integers. In the Mathematica language, there's also a range function Range[a,b,c]. Here, the arguments can be either real numbers or exact fractions. If one of the input argument is a decimal, then the computation is done as machine precision approximations and the result list's elements are also in decimals. If all inputs are in fractions (including integers), returned list's elements will also be exact fractions. In Mathematica, the language support fractions wherever a number is used, and if all numbers are specified as fractions (or integers) in the code, the result of the computation is also in exact fractions, with it automatically in a reduced fraction form where common factors in the numerator and denominator are taken out. (Fractions in Mathematica is written as a/b with a and b integers.) This section compares the expressiveness of a particular list generating facility in 3 languages. But far more importantly, being able to compute with fractions naturally is a expressibility unheard of in non-commercial languages. Example: Rich, Systematic Parameters for Functions In many languages, there is a function called “map”. Usually it takes the form map(f, myList) and returns a list where f is applied to every element in myList. For example, here is a example from Python
Re: Xah's Edu Corner: What is Expressiveness in a Computer Language
"Xah Lee" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > What is Expressiveness in a Computer Language PLONK. -- Dag. -- http://mail.python.org/mailman/listinfo/python-list
Re: python library for web discussions
Amir Michail wrote: > Hi, > > I'm building something like digg/reddit and would like to allow people > to have discussions on various items. > > Is there a simple lightweight python library that I can use (as opposed > to a heavyweight web framework)? Although not necessary, some sort of > scoring/moderation mechanism would be good also (e.g., like > reddit/slashdot). If you don't mind that it is not possible to discuss in "threads", you may want to have a look at my blog server "Frog": http://snakelets.sourceforge.net/frog/ Ah, it doesn't support a scoring/moderation system too. So it may not really suit your needs, but if you can't find something else ;-) --Irmen -- http://mail.python.org/mailman/listinfo/python-list
Re: Xah's Edu Corner: What is Expressiveness in a Computer Language
"Dag Sunde" <[EMAIL PROTECTED]> wrote: > "Xah Lee" <[EMAIL PROTECTED]> wrote in message > news:[EMAIL PROTECTED] >> What is Expressiveness in a Computer Language > > PLONK. Don't post PLONK messages you idiot. PLONK in silence instead of adding to a lot of garbage in serveral groups. -- John Bokma Freelance software developer & Experienced Perl programmer: http://castleamber.com/ -- http://mail.python.org/mailman/listinfo/python-list
cmp() on integers - is there guarantee of returning only +-1 or 0?
doc says that it must be > 0, or < 0, but it seems that it returns +1 or -1. Can it be reliably used to get the sign of x: cmp(x, 0) like pascal Sign() function does? I mean, I'm pretty sure that it can be used, but is it mentioned somewhere in language spec, or it may be implementation defined? If so, any other simple means of _reliably_ getting the sign? -- http://mail.python.org/mailman/listinfo/python-list
Re: Initializing a list of lists
[EMAIL PROTECTED] wrote: > I want to create a list of lists, each of which is identical, but which > can be modified independently i.e: > x = [ [0], [0], [0] ] x[0].append(1) x > [[0, 1], [0], [0]] > > The above construct works if I have only few items, but if I have many, > I'd prefer to write N =3 x =N*[[0]] x > [[0], [0], [0]] > > If I now try extending the lists indepently, I cannot, as they all > point to the same list object x[0].append(1) x > [[0, 1], [0, 1], [0, 1]] > > Is there a simple way to create a list of independent lists? Try this... x, y, value = 3, 3, 0 L = [[value]*x for i in xrange(y)] Cheers, Ron -- http://mail.python.org/mailman/listinfo/python-list
How to check if a directory is exist in python?
I check the documentation here, but it does not say how to check if a directory is exist in python? http://docs.python.org/lib/os-file-dir.html And why mkdir fails if the directory already exists? Thank you. -- http://mail.python.org/mailman/listinfo/python-list
Re: Xah's Edu Corner: What is Expressiveness in a Computer Language
"John Bokma" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > "Dag Sunde" <[EMAIL PROTECTED]> wrote: > >> "Xah Lee" <[EMAIL PROTECTED]> wrote in message >> news:[EMAIL PROTECTED] >>> What is Expressiveness in a Computer Language >> >> PLONK. > > Don't post PLONK messages you idiot. PLONK in silence instead of adding to > a lot of garbage in serveral groups. Sometimes you need to make a statement about a local troll. Though I agree - a massively cross posted thread with no one familiar probably doesn't qualify -- LTP :) -- http://mail.python.org/mailman/listinfo/python-list
Re: python library for web discussions
Take a look at Karrigell (http://www.karrigell.com), it has a built-in forum application Regards, Pierre -- http://mail.python.org/mailman/listinfo/python-list
Re: A Frame-space syntax ? - Re: global, globals(), _global ?
Marc 'BlackJack' Rintsch wrote: > In <[EMAIL PROTECTED]>, robert wrote: > > >>The fact is: >>* Python has that big problem with unnecessary barriers for nested frame >>access - especially painfull with callback functions where you want to >>put back data into the calling frame. > > > You mean accessing the locals in the function that invoked the callback!? > That sounds ugly. Makes it hard to decouple the caller and the callee > here. > That is a frequent need. For read's its anyway wired up. E.g. callbacks: def f(): a=1 def g(var): print a # automatic .lastvar=var# binds in outer frame run_w_callback(1,2,g) print lastvar Ruby blocks for example do that regularly. Robert -- http://mail.python.org/mailman/listinfo/python-list
Re: Relative paths in mod_python
Ivo van der Sangen wrote: > I was wondering if I could use relative paths in a mod_python script. At > the moment I am defining a constant string > "/path/to/dir/where/script/resides". The problem with this is that when > I move the script including files I use to get metadata I have to change > this variable. The same problem occurs when I distribute the script; the > person using it will first have to modify it, which is not what I want. Is > it possible that a mod_python script has as current working directory > the directory where the script resides? At the moment os.getcwd() > returns '/'. import os req.write(os.path.abspath(__file__)) seems to give you the absolute path to the module you are executing. You can use the other os.path primitives to extract the directory from that and use it to locate the associated data files. regards Steve -- Steve Holden +44 150 684 7255 +1 800 494 3119 Holden Web LLC/Ltd www.holdenweb.com Love me, love my blog holdenweb.blogspot.com -- http://mail.python.org/mailman/listinfo/python-list
PyWeek #2 one week before the fun starts!
The PyWeek challenge invites entrants to write a game in one week from scratch either as an individual or in a team. Entries must be developed in Python, during the challenge, and must incorporate some theme chosen at the start of the challenge. PyWeek #2 runs from Sunday 26th March to Sunday 2nd April (00:00UTC to 00:00UTC). THEME VOTING HAS STARTED -- To register for the challenge, visit: http://www.pyweek.org/ -- http://mail.python.org/mailman/listinfo/python-list
global statement and scoping
Hi everyone, I am compiling the following script using Py_CompileString def compute(node): #global compute iter = node.getChild(0) while iter: if isinstance(iter, Group): compute(iter) print iter iter = iter.next compute(self.a0) The I evaluate the script using PyEval_EvalCode and get a ''global name "compute" is not defined' error at the line of the recursive call. When I comment in the "global" statement at the beginning of the function then everything works fine. What's strange is the once I comment out the statement again it still works... Somewhere something is written into a dictionary in dunno where ? Is it normal to have the global statement at the beginning of a function like that ? Cheers Jochen -- http://mail.python.org/mailman/listinfo/python-list
Re: cmp() on integers - is there guarantee of returning only +-1 or 0?
"Dmitry Anikin" <[EMAIL PROTECTED]> writes: > doc says that it must be > 0, or < 0, but it seems that > it returns +1 or -1. Can it be reliably used to get the sign of x: > cmp(x, 0) like pascal Sign() function does? The doc says (http://docs.python.org/lib/built-in-funcs.html): cmp(x,y) Compare the two objects x and y and return an integer according to the outcome. The return value is negative if x < y, zero if x == y and strictly positive if x > y. > I mean, I'm pretty sure that it can be used, but is it mentioned > somewhere in language spec, or it may be implementation defined? The doc doesn't specify that it returns -1/0/+1 so by definition it's implementation defined. > If so, any other simple means of _reliably_ getting the sign? Ehh, every way I see offhand is at least a little bit messy. -- http://mail.python.org/mailman/listinfo/python-list
Re: How to check if a directory is exist in python?
Check out os.path.isdir(path_name) http://docs.python.org/lib/module-os.path.html -- http://mail.python.org/mailman/listinfo/python-list
Re: How to check if a directory is exist in python?
<[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] |I check the documentation here, but it does not say how to check if a | directory is exist in python? | http://docs.python.org/lib/os-file-dir.html Look at the exist or isdir methods of the os.path module (http://docs.python.org/lib/module-os.path.html} | | And why mkdir fails if the directory already exists? If you prefer a "more friendly" approach you may wanna take a look at Trent Mick's _mkdir which is located at http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/82465 | Regards, Vincent Wehren | Thank you. | -- http://mail.python.org/mailman/listinfo/python-list
Pycrypto - active ??
Does anyone know if pycrypto is active at all. I have been browsing
groups etc. for some info and have found entries from 2003 (latest)
regarding some bits I was looking for in particular reference to
symmetrical encoding (AES) and auto padding and supply or not of iv to
set up method i.e
from Crypto.Cipher import AES
from Crypto.Hash import SHA256
import random
import zlib
s = SHA256.new()
s.update('secret')
key = s.digest()
x = AES.new(key, AES.MODE_CBC) # should be (key,AES.MODE_CBC,iv)
iv should according to docs (which also look very old) should be a
random number equal to the size of data blocks (in CBC or EBC). Does
anyone know if by not supplying iv - is the data secure or not ??
Auto iv and auto padding would help this project a lot but unknown as
to whether they exist. I may be missing an important point here though
- so correct me where you will.
It would appear to be a great shame if pyCrypto has stalled or not
taken on board more seriously, there's great talk of implementing TLS,
SSL etc. in the lists but little support of this visible in code or
docs. The docs examples don't exist in code but getting them from ATTIC
in cvs shows they are not stable, possibly not secure and not
representative of the code now (and that's a couple of years ago)
as an aside I have found a way to pad and remove padding at decrypt is
quite simple, use zlib.compress -> pad -> encrypt
then
decrypt -> zlib.decompress and its just your data minus padding.
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Re: How to check if a directory is exist in python?
"Vincent Wehren" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] | <[EMAIL PROTECTED]> wrote in message | news:[EMAIL PROTECTED] ||I check the documentation here, but it does not say how to check if a || directory is exist in python? || http://docs.python.org/lib/os-file-dir.html | | Look at the exist or isdir methods of the os.path module Ofcourse I mean "exists"... | (http://docs.python.org/lib/module-os.path.html} | || || And why mkdir fails if the directory already exists? | | If you prefer a "more friendly" approach you may wanna take a look at Trent | Mick's _mkdir which is located at | http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/82465 || | | Regards, | Vincent Wehren | || Thank you. || | | -- http://mail.python.org/mailman/listinfo/python-list
Re: Getting .NET SDK to work with Python 2.4.2
"Dave" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] | So this means that I have to download .NET 1.1 SDK. Visual Studio 8 | comes with msvcrt.lib, but im assuming it's the wrong version. | Yes, I'd say so. -- Vincent Wehren -- http://mail.python.org/mailman/listinfo/python-list
Re: How to check if a directory is exist in python?
Vincent Wehren wrote: > | <[EMAIL PROTECTED]> wrote in message > | news:[EMAIL PROTECTED] > ||I check the documentation here, but it does not say how to check if a > || directory is exist in python? > || http://docs.python.org/lib/os-file-dir.html > | > | Look at the exist or isdir methods of the os.path module > > Ofcourse I mean "exists"... > You also mean "functions", not "methods". *Classes* have methods. regards Steve -- Steve Holden +44 150 684 7255 +1 800 494 3119 Holden Web LLC/Ltd www.holdenweb.com Love me, love my blog holdenweb.blogspot.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Have you ever considered of mousing ambidextrously?
Aahz wrote: > Heh. When possible, my work situation includes two computers, each with > their own keyboard and mouse. To put the keyboards as close together as > possible, the mice go on the outside. I prefer a similar setup with 2 duel monitor PCs (one Linux, one Windows), but use x2vnc to control both with one keyboard and mouse. Unfortunately neither x2vnc or Synergy really fulfill my needs though, so I'm working on a replacement. Actually I'm writing this email instead of working on it, back to the (Vim) mines. -- Benji York -- http://mail.python.org/mailman/listinfo/python-list
Re: Pycrypto - active ??
Well, the homepage of Pycrypto (http://www.amk.ca/python/code/crypto) was modified las in December 2005 - quite recent imo. It is used e.g. in the paramiko package (http://www.lag.net/paramiko/) for the most(?) used ssh implementation in Python, so my guess it is active. -- http://mail.python.org/mailman/listinfo/python-list
Re: cmp() on integers - is there guarantee of returning only +-1 or 0?
It is depending on the classes you try to compare, and on how the comparison functions (see http://docs.python.org/ref/customization.html) are implemented in these, see example below: py> class wrong(object): ... def __init__(self, x): ... self.x = x ... def __cmp__(self, other): ... if self.x < other.x: ... return -1 ... else: ... return 1 ... py> class right(object): ... def __init__(self, x): ... self.x = x ... def __cmp__(self, other): ... if self.x < other.x: ... return -1 ... elif self.x > other.x: ... return 1 ... else: ... return 0 ... py> w1 = wrong(1) py> w2 = wrong(1) py> cmp(w1, w2) 1 py> py> r1 = right(1) py> r2 = right(1) py> cmp(r1, r2) 0 -- http://mail.python.org/mailman/listinfo/python-list
Re: Xah's Edu Corner: What is Expressiveness in a Computer Language
On 19 Mar 2006 13:03:18 -0800, "Xah Lee" <[EMAIL PROTECTED]> wrote, quoted or indirectly quoted someone who said : >One thing commonly misunderstood in computing industry is the notion of >expressiveness. If a language has a vocabulary of (smile, laugh, grin, >giggle, chuckle, guffaw, cackle), Expressive for a natural language refers to the language's ability to generate precisely generate moods, and move people emotionally in a minimum of words. Expressiveness in computer languages refers to the language's ability to persuade the computer to produce some result in a minimum of words. Another measure might be how smoothly elements of the language map onto elements of the problem domain. -- Canadian Mind Products, Roedy Green. http://mindprod.com Java custom programming, consulting and coaching. -- http://mail.python.org/mailman/listinfo/python-list
Re: Unpythonic? Impossible??
BrJohan wrote: > I know how to use a class factory - and could work around using such a > mechanism. However I am interested to know if I could let the classes do the > work by themselves. You can, but a class factory is going to be much clearer and probably more maintainable. From the user's perspective, there's no difference from calling a class A to instantiate it, and calling a factory function called A that selects the appropriate class and returns an instance of it. -- Erik Max Francis && [EMAIL PROTECTED] && http://www.alcyone.com/max/ San Jose, CA, USA && 37 20 N 121 53 W && AIM erikmaxfrancis Never had very much to say / Laugh last, laugh longest -- Des'ree -- http://mail.python.org/mailman/listinfo/python-list
Re: C-API: A beginner's problem
Fabian Steiner wrote:
> I recently started learning C since I want to be able to write Python
> extension modules. In fact, there is no need for it, but I simply want
> to try something new ...
>
> I tried to implement the bubblesort algorithm in C and to use it in
> python; bubblesort.c compiles fine, but whenever I want to import the
> modul and call the function I get a segmentation fault. This is what the
> code looks like:
>
> static PyObject *py_bubblesort(PyObject *self, PyObject *args) {
> PyObject *seq = NULL, *item, *newseq = NULL;
> int seqlen, i;
long it;
> if(!PyArg_ParseTuple(args, "O", &seq)) {
> return NULL;
> }
> seq = PySequence_Fast(seq, "argument must be iterable");
> if(!seq) {
> return NULL;
> }
> seqlen = PySequence_Fast_GET_SIZE(seq);
> int list[seqlen];
> for (i = 0; i <= seqlen; i++) {
That is one iteration too much. Use
for (i = 0; i < seglen; i++)
> item = PySequence_Fast_GET_ITEM(seq, i);
Now item is a PyObject*. You'll have to convert it to an integer now:
it = PyInt_AsLong(item);
if (it == -1 && PyErr_Occurred()) {
Py_DECREF(seq);
/* set a new exception here if you like */
return NULL;
}
> list[i] = it;
> }
> bubblesort(list, seqlen);
> newseq = PyList_New(seqlen);
> if(!newseq) {
Do not forget to DECREF seq:
Py_DECREF(seq);
> return NULL;
> }
> for(i = 0; i < seqlen; i++) {
> PyList_SetItem(newseq, i, list[i]);
List items must be PyObject*s, not plain ints. Use:
PyList_SetItem(newseq, i, PyInt_FromLong(list[i]));
(This is sloppy error checking, but if PyInt_FromLong fails you're out of
memory anyways ;)
> }
Again, seq is not needed anymore:
Py_DECREF(seq);
> return newseq;
>
> bubblesort(int list[], int seqlen) is doing the actual job and it is
> working.
>
> What did I do wrong? As I am quite new to C, I probably made many
> mistakes, so please feel free to correct me.
There's quite a bit you can overlook, especially stale references to PyObjects.
I'm not even sure the code compiles or runs correctly with my corrections ;)
Cheers,
Georg
--
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