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

Thread Question
by Ritesh Raj Sarraf Aug. 2, 2006

Aug. 2, 2006

Hi, I have some basic doubts about thread. I have a list which has items in it which need to be downloaded from the internet. Let's say list is: list_items[] which has 100 items in it. I have a function download_from_web() which does the work of downloading the items from the web. It does error handling in case it gets errors like 404 et cetera. Currently, this is how I'm using it. for item in list_items: download_from_web(item) This way, one items is downloaded at a time. I'm planning to implement threads in my application so that multiple items can be downloaded concurrently. I want the thread option to be user-defined. Looking at the documentation of threads (Core Python Programming), I've noticed that all threads are executed a once. Depending upon what they are doing, some finish early and some later. But I want to implement something like: for item in list_items: for num in thread_args: thread[num].start() thread[num].start() Is this the correct way of threading applications ? This is the first time I'd be doing threading. So was looking for comments and suggestions. Thanks, Ritesh

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Pickle vs XML for file I/O
by crystalattice Aug. 2, 2006

Aug. 2, 2006

I'm creating an RPG for experience and practice. I've finished a character creation module and I'm trying to figure out how to get the file I/O to work. I've read through the python newsgroup and it appears that shelve probably isn't the best option for various reasons. This lead me to try messing w/ pickle, but I can't figure out how to use it with classes. I've found many examples of using pickle w/ non-OOP code but nothing that shows how to use it w/ classes, subclasses, etc. I've read the documentation but it doesn't explain it well enough for me. Then I started thinking perhaps I'm going about it wrong. My current thought is to save an instance of each character so all the info (name, skills, hit points, etc.) is stored in one place. But looking at OpenRPG made me think that perhaps using XML to store the information would be better. Each character could have a separate XML file, though I don't know how it would work if many NPC's are required. I guess my question is, what are the benifits of getting pickle to work w/ my classes vs. converting all the character data into XML and just writing that to a file? Since most of the data would need to be modified often, e.g. hit points, is one storage format better than the other? Can you even modify data if it's been pickled w/o having to unpickle it, change the data, then repickle it?

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Dr. Dobb's Python-URL! - weekly Python news and links (Aug 2)
by Cameron Laird Aug. 2, 2006

Aug. 2, 2006

QOTW: "[U]sing Python is not programming, it IS a fun!" - Tolga "The reason for making complex a builtin is _not_ to ease a single program, but to create a convention allowing different modules which operate on complex numbers to communicate." -Scott David Daniels Komodo 4.0 debuted at last week's OSCON: http://www.activestate.com/komodo/beta Python2.5final is under two weeks away. Watch for it. 'Want to *really* learn Python? http://home.earthlink.net/~python-training/public.html Quest for the Holy Grail is as Pythonic as it gets: http://www.cosc.canterbury.ac.nz/greg.ewing/grailquest/index.html John Henry asks a sober question which Simon Brunning can't refrain from soiling with his perverse algorithmic imagination: http://groups.google.com/group/comp.lang.python/msg/bb47da1c1c346954 C has static locals. Python has classes, closures, and defaulted keyword parameters: http://groups.google.com/group/comp.lang.python/browse_thread/t hread/9799c58168e0615b/ Python range()s the way Dijkstra preaches: http://www.cs.utexas.edu/users/EWD/transcriptions/EWD08xx/EWD831.html ======================================================================== Everything Python-related you want is probably one or two clicks away in these pages: Python.org's Python Language Website is the traditional center of Pythonia http://www.python.org Notice especially the master FAQ http://www.python.org/doc/FAQ.html PythonWare complements the digest you're reading with the marvelous daily python url http://www.pythonware.com/daily Mygale is a news-gathering webcrawler that specializes in (new) World-Wide Web articles related to Python. http://www.awaretek.com/nowak/mygale.html While cosmetically similar, Mygale and the Daily Python-URL are utterly different in their technologies and generally in their results. For far, FAR more Python reading than any one mind should absorb, much of it quite interesting, several pages index much of the universe of Pybloggers. http://lowlife.jp/cgi-bin/moin.cgi/PythonProgrammersWeblog http://www.planetpython.org/ http://mechanicalcat.net/pyblagg.html comp.lang.python.announce announces new Python software. Be sure to scan this newsgroup weekly. http://groups.google.com/groups?oi=djq&as_ugroup=comp.lang.python.announce Python411 indexes "podcasts ... to help people learn Python ..." Updates appear more-than-weekly: http://www.awaretek.com/python/index.html Steve Bethard, Tim Lesher, and Tony Meyer continue the marvelous tradition early borne by Andrew Kuchling, Michael Hudson and Brett Cannon of intelligently summarizing action on the python-dev mailing list once every other week. http://www.python.org/dev/summary/ The Python Package Index catalogues packages. http://www.python.org/pypi/ The somewhat older Vaults of Parnassus ambitiously collects references to all sorts of Python resources. http://www.vex.net/~x/parnassus/ Much of Python's real work takes place on Special-Interest Group mailing lists http://www.python.org/sigs/ Python Success Stories--from air-traffic control to on-line match-making--can inspire you or decision-makers to whom you're subject with a vision of what the language makes practical. http://www.pythonology.com/success The Python Software Foundation (PSF) has replaced the Python Consortium as an independent nexus of activity. It has official responsibility for Python's development and maintenance. http://www.python.org/psf/ Among the ways you can support PSF is with a donation. http://www.python.org/psf/donate.html Kurt B. Kaiser publishes a weekly report on faults and patches. http://www.google.com/groups?as_usubject=weekly%20python%20patch Although unmaintained since 2002, the Cetus collection of Python hyperlinks retains a few gems. http://www.cetus-links.org/oo_python.html Python FAQTS http://python.faqts.com/ The Cookbook is a collaborative effort to capture useful and interesting recipes. http://aspn.activestate.com/ASPN/Cookbook/Python Among several Python-oriented RSS/RDF feeds available are http://www.python.org/channews.rdf http://bootleg-rss.g-blog.net/pythonware_com_daily.pcgi http://python.de/backend.php For more, see http://www.syndic8.com/feedlist.php?ShowMatch=python&ShowStatus=all The old Python "To-Do List" now lives principally in a SourceForge reincarnation. http://sourceforge.net/tracker/?atid=355470&group_id=5470&func=browse http://www.python.org/dev/peps/pep-0042/ The online Python Journal is posted at pythonjournal.cognizor.com. editor(a)pythonjournal.com and editor(a)pythonjournal.cognizor.com welcome submission of material that helps people's understanding of Python use, and offer Web presentation of your work. del.icio.us presents an intriguing approach to reference commentary. It already aggregates quite a bit of Python intelligence. http://del.icio.us/tag/python *Py: the Journal of the Python Language* http://www.pyzine.com Archive probing tricks of the trade: http://groups.google.com/groups?oi=djq&as_ugroup=comp.lang.python&num=100 http://groups.google.com/groups?meta=site%3Dgroups%26group%3Dcomp.lang.pyth… Previous - (U)se the (R)esource, (L)uke! - messages are listed here: http://www.ddj.com/topic/python/ (requires subscription) http://groups-beta.google.com/groups?q=python-url+group:comp.lang.python*&s… http://purl.org/thecliff/python/url.html (dormant) or http://groups.google.com/groups?oi=djq&as_q=+Python-URL!&as_ugroup=comp.lan… There is *not* an RSS for "Python-URL!"--at least not yet. Arguments for and against are occasionally entertained. Suggestions/corrections for next week's posting are always welcome. E-mail to <Python-URL(a)phaseit.net> should get through. To receive a new issue of this posting in e-mail each Monday morning (approximately), ask <claird(a)phaseit.net> to subscribe. Mention "Python-URL!". Write to the same address to unsubscribe. -- The Python-URL! Team-- Dr. Dobb's Journal (http://www.ddj.com) is pleased to participate in and sponsor the "Python-URL!" project.

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Re: Using Python for my web site
by Luis M. González Aug. 2, 2006

Aug. 2, 2006

Cliff Wells wrote: > On Mon, 2006-07-31 at 22:25 -0700, Luis M. González wrote: > > I don't have experience with Django or any other python framework, but > > I have used bare-bones mod_python and it rocks. > > I wouldn't use PSP though... > > It is not very polished, and they way it handles the "indentation > > problem" in python is a little bit confussing. > > > > IMHO the best way of using mod_python is with its publisher handler. > > It let's you code your applications in a MVC (model view controller) > > style. > > While I agree (or at least consider the point moot) that this is > possibly the best way to use plain mod_python, I'd disagree that it's a > good way to develop modern web applications in Python. By the time > you've decided on every bit of framework to use, and made all the little > decisions that go into turning a fresh, clean spot on your hard drive > into an application, what you've done is reinvent TurboGears rather than > develop your application. Worse, you've probably reinvented it poorly. > I've done so many times and am well aware of what a time-waster it is. > > You say that you haven't tried Django or any other Python framework. > Perhaps you should. You seem to have at least the start of the right > idea about web application organization, so I think you'd be pleasantly > surprised with what you'll find already done for you by the major Python > frameworks and how much time you'll stop wasting on code that isn't part > of your application. > > Regards, > Cliff Well... yes, you're right. I guess that the reason for not having used a framework already is laziness... I have experience with Karrigell, which rocks too, but it lacks some deployment options (no mod_python, no fastcgi, etc). And as far as I could see in the Django docs, I should learn many new things to do exactly the same, such as yet another templating language or how to map urls with regular expressions (I still couldn't wrap my head around regex... I find them very boring to learn...). But you are absolutely right. I should definetely try Django sometime. I guess I'll do it when I have a real need to do some serious web stuff. As for TurboGears, I'm not very impressed... This is a pile of different components picked by someone according to his liking, very well glued together. Althouh its quality may be good, why should I stick with a number of components chosen according the criteria of some other guy? For example, why kid instead of Cheetah? Why CherryPy? Really, it isn't that hard to install cheetah and, if you want an object relational mapper, sqlobject. Once you have them, using raw mod_python is just a pleasure. I feel I'm in front of a white clean canvas and I just start coding. I like the flexibility of being able to choose each part of "my own framework". I even created a small script that does the automatic crud stuff for me (not as polished as Django for sure, but it works like a charm). Anyway, there's still an issue with using these frameworks: Availability. It's very hard, if not impossible, to find a decent web host at an affordable price. Although I guess many of those who use Django, for example, run their own host. Being able to use raw mod_python gives you an advantage here. Luis

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Newbie Q: Class Privacy (or lack of)
by Steve Jobless Aug. 2, 2006

Aug. 2, 2006

Hi, I just started learning Python. I went through most of the tutorial at python.org. But I noticed something weird. I'm not talking about the __private hack. Let's say the class is defined as: class MyClass: def __init__(self): pass def func(self): return 123 But from the outside of the class my interpreter let me do: x = MyClass() x.instance_var_not_defined_in_the_class = 456 or even: x.func = 789 After "x.func = 789", the function is totally shot. Are these bugs or features? If they are features, don't they create problems as the project gets larger? TIA, SJ

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Re: Nested function scope problem
by Antoon Pardon Aug. 2, 2006

Aug. 2, 2006

On 2006-08-02, Dennis Lee Bieber <wlfraed(a)ix.netcom.com> wrote: > On 2 Aug 2006 13:09:26 GMT, Antoon Pardon <apardon(a)forel.vub.ac.be> > declaimed the following in comp.lang.python: > >> >> And how is this all relevant in deciding that the source language for >> the above interpreter actions isn't C? What the interpreter does is >> the following: >> >> Get the addres of the variable c >> Get the value that is at that address. >> Add 100 to this value >> Store the new value at that address. >> >> Please explain what is wrong in this sequence of actions >> for an interpretation of the C statement: "c = c + 100;" > > What interpretation will your hypothetical give for: > > c = &c + 1 > c++ > > and > > d = *(1000) #I'll concede this one may be a bit invalid > #I don't recall if a cast is needed Why should I answer this? You stated that my interpreter couldn't be interpreting the C-language. You did that before you asked these questions. So it seems your decision for your statement is not dependend om my answer for these questions. So please clarify how you came to your decision. -- Antoon Pardon

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Newbie Cygwin Q
by Gerry Blais Aug. 2, 2006

Aug. 2, 2006

I'm trying to install and run, on XP, a queueing analysis package, PDQ, which has a{ Python, swig, C library version}. I'm new to Cygwin (but not to Unix). After installing Cygwin and Python, there is a Python2.4.exe in /lib. If I have a file with #!/lib/Python2.4.exe Print "hello" and I do the chmod, and submit ./hello.py I get a message "hello.py is currently being printed" and nothing happens, until I give up and ^C out. or, now, with no changes I can see, Can't find file hello What am I missing? Thanks, Gerry

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PyImport_Import() failed
by Yang Fan Aug. 2, 2006

Aug. 2, 2006

Hello, I'm new to Python.I want to embed Python interpreter into my C++ application powered by Borland C++ Builder 2006. I have written some C++ code in order to evaluate Python script file, but PyImport_Import() calls failed.I really don't know what's wrong with my cpp code.It always return a NULL value. Any advice is appreciated! int TPython::ExecuteScript(const char * pszFileName) { PyObject *pFileName, *pModule, *pDict, *pFunc; PyObject *pArgs, *pValue; pFileName = PyString_FromString(pszFileName); /* Error checking of pFileName left out */ if(!pFileName) { trace1(("pFileName == NULL ")); } pModule = PyImport_Import(pFileName); // always failed, returned NULL:( Py_DECREF(pFileName); if (pModule != NULL) { ................ } else { PyErr_Print(); trace1(("Failed to load \"%s\"\n", pszFileName)); return 1; } return 0; }

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how to get size of unicode string/string in bytes ?
by pattreeya＠gmail.com Aug. 2, 2006

Aug. 2, 2006

Hello, how can I get the number of byte of the string in python? with "len(string)", it doesn't work to get the size of the string in bytes if I have the unicode string but just the length. (it only works fine for ascii/latin1) In data structure, I have to store unicode string for many languages and must know exactly how big of my string which is stored so I can read back later. Many thanks for any suggestion. cheers! pattreeya.

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Re: Convert string to mathematical function
by jeremito Aug. 2, 2006

Aug. 2, 2006

I was unaware of the exec and eval functions in Python. Without trying them, they seem to be what I want to do. I'll play around with it and see if I can figure it out. Thanks for the suggestions everyone. Jeremy

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