🌐 Mailman 3 December 2006 - Python-list - python.org

Is python memory shared between theads?
by Wesley Henwood Dec. 1, 2006

Dec. 1, 2006

So I declare a variable named A in thread1, in script1.py. I assign the value of 2.5 to A. I then run script2.py in thread2. Script2.py assigns the value of 5.5 to a variable named A. Now, when thread1 resums execution, I see that A = 5.5, rather than 2.5 as I expected. Is this normal behavior? Based on the little documentation I have been able to find on this topic, it is normal behavior. The only way to use same-named variables in scripts is to have them run in a different process, rather than different threads.

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Re: I/O Multiplexing and non blocking socket
by Salvatore Di Fazio Dec. 1, 2006

Dec. 1, 2006

Jean-Paul Calderone ha scritto: > On 1 Dec 2006 06:07:28 -0800, Salvatore Di Fazio <salvatore.difazio(a)gmail.com> wrote: > >Hi guys, > >I'm looking for a tutorial to make a client with a i/o multiplexing and > >non blocking socket. > > > >Anybody knows where is a tutorial? > > http://twistedmatrix.com/projects/core/documentation/howto/clients.html > > Jean-Paul Thank you guys, but I would like to use the standard libraries

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client/server design and advice
by TonyM Dec. 1, 2006

Dec. 1, 2006

I recently completed the general guidelines for a future project that I would like to start developing...but I've sort of hit a wall with respect to how to design it. In short, I want to run through approximately 5gigs of financial data, all of which is stored in a large number of text files. Now as far as formatting and data integrity...I would go through and ensure that each file had the required setup so thats not really the issue. The problem I am having is with respect to speed. The languages I knew the best when coming into this project includes c++ and php. However, I then thought about how long it would take one PC to iterate through everything and figured it would probably take a significant amount of time. As such, I started looking into various languages and python caught my interest the most due to its power and what seems to be ease of use. I was going to initially just use python as a means of creating various indicators (i.e. calculations that would be performed on the data in the file)...however I am leaning towards moving to python entirely mostly due to its gui support. First off, i was wondering if this is a reasonable setup: The entire process would involve a server which manages which pc is processing which set of data (which may be a given text file or the like), and a client application which i would run on a few pc's locally when they aren't in use. I would have a database (sqlite) holding all calculated data of significance. Each client will basically login/connect with the server, request a time interval (i.e. does anything need processed? if so what data should i look at), and then it would update its status with the server which would place a lock on that data set. One thing i was wondering is if it would be worth it to use c++ for the actual iteration through the text file or should i simply use python? While i'm sure that c++ would be faster i am not entirely sure its worth the headache if its not going to save me significant processing time. Another thing is...if i was going to work with python instead of c++, would it be worth it to import all of the data into an sqlite database before hand (for speed issues)? Lastly, as far as the networking goes, i have seen posts and such about something called Pyro (http://pyro.sourceforge.net) and wondered if that was worth looking into for the client/server interaction. I apologize if any of these questions are more lower level, this is simply the first client/server application ive created and am doing so in a language ive never used before ;) Thanks for the help -Tony

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Re: detecting that a SQL db is running
by bill ramsay Dec. 1, 2006

Dec. 1, 2006

thank you paul, much appreciated

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Re: Python25.zip
by Colin J. Williams Dec. 1, 2006

Dec. 1, 2006

Dennis Lee Bieber wrote: > On Thu, 30 Nov 2006 18:14:11 -0500, "Colin J. Williams" > <cjw(a)sympatico.ca> declaimed the following in comp.lang.python: > >> As part of the Python initialization, C:\Windows\System32\Python25.zip >> is set up in the path. >> >> I haven't seen any documentation on the use or purpose of the zip file. >> > Well, did you examine the contents of it? There is no such file in C:\Windows\System32 - Python 2.5 on a Windows XP > > I believe for some versions now, "import" can pull from a ZIP > archive -- perhaps they've put the many standard library imports into a > single file... Yes, since 2.3 - thanks to Fredrick for the pointer to PEP 273. That gives the helpful warning that the above should follow the home directory in the path list. PEP 302 says "[PYTHONPATH] is directly needed for Zip imports." The role of Python25.zip is not clear. Is it required in the path just to enable the import X.zip capability? Colin W.

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Re: detecting that a SQL db is running
by bill ramsay Dec. 1, 2006

Dec. 1, 2006

Dennis none of this matters, all i am trying to find out is whether or not the local MSDE is actually running. I put all the other bits in there to try and put some background to it. kind regards bill

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Re: python vs java & eclipse
by Amir Michail Dec. 1, 2006

Dec. 1, 2006

krishnakant Mane wrote: > just used the py dev plugin for eclipse. > it is great. But isn't support for java better because the eclipse ide can take advantage of explicit type declarations (e.g., for intellisense, refactoring, etc.)? Amir > auto indentation and intellisence. > and all other things. > so now how does it look from this end? > python + productivity and eclipse + productivity = double productivity! > only problem with the plugin is that I find it difficult to manage the > script running. > I open a command prompt and run the scripts manually. > any suggestion for this. > for example I had name = raw_input("please enter your name") and the > moment I type the first letter on the keyboard the code execution > moves over to the next statement. should it not wait for the return > key as it always does? > Krishnakant.

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Re: Python popenX() slowness on AIX?
by allenjo5＠mail.northgrum.com Dec. 1, 2006

Dec. 1, 2006

Stefaan A Eeckels wrote: > On 21 Nov 2006 13:02:14 -0800 > allenjo5(a)mail.northgrum.com wrote: > > > The fact that it does this in Python code instead of C is the main > > cause of the slowness. So, unless Python is changed to do this in C, > > it's always going to be slow on AIX :-( > > I guess that the reason it's slow is that there are many descriptors to > try and close. Reducing them using ulimit -n could improve the speed. > > AIX has a fcntl command to close all open file descriptors from a > descriptor onwards: > > fcntl(3, F_CLOSEM); > > This of course should be used instead of the loop: > > import sys > import fcntl > > __all__ = ["popen2", "popen3", "popen4"] > > ... > > def _run_child(self, cmd): > if isinstance(cmd, basestring): > cmd = ['/bin/sh', '-c', cmd] > try: > os.fcntl(3, 10, 0) > except OSError: > pass > try: > os.execvp(cmd[0], cmd) > finally: > os._exit(1) > > 10 happens to be the value of F_CLOSEM (from /usr/include/fcntl.h). > I've currently no access to an AIX system with Python, but it could be > worth trying. Yes, very much worth it. F_CLOSEM is _so_ much better than the loop, even in C. Using your brilliant suggestion, I now have a simple patch to the python source that implements it for any OS that happens to have the fcntl F_CLOSEM option. It is below in its entirety. I believe I got the try: stuff correct, but since I'm new to Python, I'd appreciate any comments. I have another patch to implement my os.rclose(x,y) method, which would improve the speed of popenX() for the OSes that don't have F_CLOSEM, by doing the close() loop in C instead of Python, but I don't know if it would be as likely to be accepted as this probably would be. Now, where do I send my proposed patch for consideration? John. --- ./Modules/fcntlmodule.c.orig Thu Jun 3 08:47:26 2004 +++ ./Modules/fcntlmodule.c Fri Nov 24 11:18:23 2006 @@ -545,6 +545,11 @@ if (ins(d, "DN_MULTISHOT", (long)DN_MULTISHOT)) return -1; #endif +/* For systems like AIX that have F_CLOSEM to close multiple fds */ +#ifdef F_CLOSEM + if (ins(d, "F_CLOSEM", (long)F_CLOSEM)) return -1; +#endif + #ifdef HAVE_STROPTS_H /* Unix 98 guarantees that these are in stropts.h. */ INS(I_PUSH); --- ./Lib/popen2.py.orig Thu Feb 10 08:46:14 2005 +++ ./Lib/popen2.py Fri Nov 24 11:37:15 2006 @@ -8,6 +8,7 @@ import os import sys +import fcntl __all__ = ["popen2", "popen3", "popen4"] @@ -65,11 +66,18 @@ def _run_child(self, cmd): if isinstance(cmd, basestring): cmd = ['/bin/sh', '-c', cmd] - for i in range(3, MAXFD): - try: - os.close(i) - except OSError: - pass + try: + if fcntl.F_CLOSEM: + try: + fcntl.fcntl(3, fcntl.F_CLOSEM, 0) + except OSError: + pass + except AttributeError: + for i in range(3, MAXFD): + try: + os.close(i) + except OSError: + pass try: os.execvp(cmd[0], cmd) finally:

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good documentation about win32api ??
by __schronos__ Dec. 1, 2006

Dec. 1, 2006

Hi all. Recently I've to developed a project in python that made operation under win32 platform and I found a lot of problema to find good information. The only one documentation is in ActivePython page (http://aspn.activestate.com/ASPN/docs/ASPNTOC-APYTH2.4.0) but it is not very good and finally I had to turn to the newsgroups (it was very nice). And the question is: ¿Anybody knows where can I find good documentation about win32api? Thanks in advanced. ScnS.

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Re: How to read the directory which the actively running python file is located in?
by anders Dec. 1, 2006

Dec. 1, 2006

in os module there is many funktion/methods to extract this information to ask the path to the current running pythonprogram you can do likes this ----- CUT----------- import os print os.getcwd() ----- CUT ------ // Anders Michael Malinowski skrev: > Is there a way to read the directory that the currently running python file > is located in? > Cheers > Mike.

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