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

for i in range() anti-pattern [was Re: trouble writing results to files]
by Steven D'Aprano Dec. 1, 2006

Dec. 1, 2006

On Wed, 29 Nov 2006 17:00:30 +0100, Fredrik Lundh wrote: > Neil Cerutti wrote: > >>> BTW, iterating over range(len(a)) is an anti-pattern in Python. >> >> Unless you're modifying elements of a, surely? > > and needs to run on a Python version that doesn't support enumerate. This isn't meant as an argument against using enumerate in the common case, but there are circumstances where iterating with an index variable is the right thing to do. "Anti-pattern" tends to imply that it is always wrong. The advantage of enumerate disappears if you only need to do something to certain items, not all of them: >>> alist = list("abcdefghij") >>> for i in xrange(3, 7, 2): ... print i, alist[i] ... 3 d 5 f Nice and clear. But this is just ugly and wasteful: >>> for i,c in enumerate(alist): ... if i in xrange(3, 7, 2): ... print i, c ... 3 d 5 f although better than the naive alternative using slicing, which is just wrong: >>> for i,c in enumerate(alist[3:7:2]): ... print i, c ... 0 d 1 f The indexes point to the wrong place in the original, non-sliced list, so if you need to modify the original, you have to adjust the indexes by hand: >>> for i,c in enumerate(alist[3:7:2]): ... print 2*i+3, c ... 3 d 5 f And remember that if alist is truly huge, you may take a performance hit due to duplicating all those megabytes of data when you slice it. If you are modifying the original, better to skip making a slice. I wrote a piece of code the other day that had to walk along a list, swapping adjacent elements like this: for i in xrange(0, len(alist)-1, 2): alist[i], alist[i+1] = alist[i+1], alist[i] The version using enumerate is no improvement: for i, x in enumerate(alist[0:len(alist)-1:2]): alist[i*2], alist[i*2+1] = alist[i*2+1], x In my opinion, it actually is harder to understand what it is doing. Swapping two items using "a,b = b,a" is a well known and easily recognised idiom. Swapping two items using "a,b = b,c" is not. -- Steven.

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Re: PIL throws exception when reading bitmap/pnm data
by Roel Schroeven Dec. 1, 2006

Dec. 1, 2006

Dennis Lee Bieber schreef: > Send a complaint to M$ requesting them to open document the NTFS > format... I've been out of the loop for a while, but the last time I > checked, NTFS was something that should be treated as read-only from > LINUX -- the recommendation was to make a small FAT-32 partition for any > data that needed to be shared. Going off-topic, but there's another way nowadays: if your Linux partitions use ext2 or ext3, you can use read/write them from Windows with the file system drivers from http://www.fs-driver.org/ -- If I have been able to see further, it was only because I stood on the shoulders of giants. -- Isaac Newton Roel Schroeven

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How to turn AUTOCOMMIT ON with cx_Oracle
by Jia Lu Dec. 1, 2006

Dec. 1, 2006

Hi all. I use cx_Oracle to connect to an Oracle9i DB. And I want to turn on AUTOCOMMIT function. I see that cur.execute("SET AUTOCOMMIT ON") cannot work. Is there any method to do that ?? Thanks a lot!

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Re: why would anyone use python when java is there?
by Mark Westwood Dec. 1, 2006

Dec. 1, 2006

may I, as a former Englishman, say how proud we always were to be exploited by our betters many thanks guv Mark Jonathan Smith wrote: > gavino wrote: > > wtf > > Java is a coffee, and coffee comes from exploited Ethiopians (they do > have some damn fine coffee, though). Most of us prefer to exploit > Englishmen instead. (damn them and their humor!) > > -smithj

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How can I change the icon
by Boneh Dec. 1, 2006

Dec. 1, 2006

Is it possible to change the icon "Tk" of the windows popped up ?

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Re: detecting that a SQL db is running
by triode＠xnet.co.nz Dec. 1, 2006

Dec. 1, 2006

Sorry if i did not make myself clear. let me try again. 1. I have a series of servers running windows server 2003. 2 on each server there is an application running that communicates with remote devices using email. 3. this application is made up from a series of modules that also extract data from a local MSDE db. 4. this application pulls emails from remote devices, interrogates a the DB, then passes on an XML message to a central server. 5. I am intercepting these XML messages to insert additional data that I extract from the DB, and then forward on to another application. Call this my local app. The problem that I have is that the original application occasionally hangs, causing the DB to stop. I have ASR routines in place to re-boot the server when this happens. I can detect when the db is up and not responding, however, if the DB does not start at all, my local application hangs. I need to find a way to determine if the DB has started, that's all. if any of you have any insight into how I can detect that the DB has started as is running, that would be very useful. any contributions, most gratefully received. kind regards bill

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RE: Python Worship
by Coates, Steve (ACHE) Nov. 30, 2006

Nov. 30, 2006

Wow! That must have been a pretty early beta. > -----Original Message----- > From: Nick [mailto:nickle@gmail.com] > Sent: 30 November 2006 17:16 > To: python-list(a)python.org > Subject: Python Worship > > http://www.sciencedaily.com/releases/2006/11/061130081347.htm > > World's Oldest Ritual Discovered -- Worshipped The Python 70,000 Years > Ago > > Nick > > > ****************************************** The information contained in, or attached to, this e-mail, may contain confidential information and is intended solely for the use of the individual or entity to whom they are addressed and may be subject to legal privilege. If you have received this e-mail in error you should notify the sender immediately by reply e-mail, delete the message from your system and notify your system manager. Please do not copy it for any purpose, or disclose its contents to any other person. The views or opinions presented in this e-mail are solely those of the author and do not necessarily represent those of the company. The recipient should check this e-mail and any attachments for the presence of viruses. The company accepts no liability for any damage caused, directly or indirectly, by any virus transmitted in this email. ******************************************

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EasyInstall under Windows - strange behaviour
by Norbert Nov. 30, 2006

Nov. 30, 2006

Hello all, i try to install ZSI under python 2.5 and windows 2000. I Downloaded the egg and tried the following c:\Python25\Scripts>easy_install.exe c:\download\ZSI-2.0_rc3-py2.5.egg The result is that pythonwin pops up and shows the file : c:\Python25\Scripts\easy_install-script.py : ---------------------------- !C:\Python25\Lib\site-packages\pythonwin\Pythonwin.exe # EASY-INSTALL-ENTRY-SCRIPT: 'setuptools==0.6c3','console_scripts','easy_install' __requires__ = 'setuptools==0.6c3' import sys from pkg_resources import load_entry_point sys.exit( load_entry_point('setuptools==0.6c3', 'console_scripts', 'easy_install')() ) ---------------------------- What is going on here ? I presume that there are some trivial things I don't understand, can someone provide apointer or hint ? Thank you for your time ! Norbert

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RE: Python Question About Compiling.
by yndesai Nov. 30, 2006

Nov. 30, 2006

I got attracted to python since I heard about PythonCAD, while I used Fortran and Basic during graduation days & VBA for some macros in Office. I liked the python as it seems smart. But without compiling it is a trouble to end user. I downloaded PythonCAD and am still searching for the libraries GLIB GTK PYGTK and what not. Then there are dependancies issues of these libs on LINUX. I am scratching my head on how I would get the PythonCAD running. Is it that no compiling facility is hindering the growth of python in commercial circuit . . . ?

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Re: Python spam?
by aahz＠pythoncraft.com Nov. 30, 2006

Nov. 30, 2006

In article <mailman.895.1164917209.32031.python-list(a)python.org>, Thomas Heller <theller(a)ctypes.org> wrote: >Aahz schrieb: >> >> Anyone else getting "Python-related" spam? So far, I've seen messages >> "from" Barry Warsaw and Skip Montanaro (although of course header >> analysis proves they didn't send it). > >I'm getting spam not only from Barry, but also from myself ;-) with >forged headers. But I'm not sure what you mean with Python-related... >Not the contents, IIRC. Thing is, I don't usually get spam "from" people I know (or at least it gets filtered before I see it), so someone is clearly using some resource of Python-related email addresses. Just seems rather odd, and I wonder whether it's some kind of DoS attack or what. -- Aahz (aahz(a)pythoncraft.com) <*> http://www.pythoncraft.com/ Member of the Groucho Marx Fan Club

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