Python-ideas May 2009

python-ideas@python.org

74 participants
41 discussions

Coloured documentation
by Konrad Delong 12 May '09

12 May '09

The documentation under http://docs.python.org/ could have different colour schemes for Python 2.5, 2.6, 2.7, 3.0, 3.1 and so on. This way one would know on sight which docs one's reading. It would also cause a lot of bikeshed talk for every release :) Konrad

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Add __nonzero__ to threading.Event
by Floris Bruynooghe 12 May '09

12 May '09

Hi I was wondering why threading.Event hasn't got the __nonzero__ special attribute? I think it would allow for code to be more pythonic if you could just do "if e: ..." instead of "if e.isSet(): ..." (or "if e.is_set(): ..." in 2.6+). The patch is trivial: Index: Lib/threading.py =================================================================== --- Lib/threading.py (revision 72551) +++ Lib/threading.py (working copy) @@ -371,6 +371,9 @@ is_set = isSet + def __nonzero__(self): + return self.__flag + def set(self): self.__cond.acquire() try: Is it worth submitting this to the tracker or is there some reason why this is a bad idea that I've missed? Regards Floris -- Debian GNU/Linux -- The Power of Freedom www.debian.org | www.gnu.org | www.kernel.org

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Add OrderedSet now that OrderedDict is in collections
by Mart Sõmermaa 09 May '09

09 May '09

There was a somewhat ancient discussion on OrderedDict and OrderedSet before: http://mail.python.org/pipermail/python-dev/2005-March/051915.html The resolution seemed to be that neither of them should be in stdlib. Now that OrderedDict is in and Raymond Hettinger has created a solid OrderedSet implementation: http://code.activestate.com/recipes/576694/ , could the latter also be included in collections? Here's a very generic use-case: def _update_key(dct, key, val): """ Update a key in dict *dct*. If they key already exists in *dct* but the value doesn't, a set of previous values is created and the value added to it. """ if key in dct: if dct[key] == val: return s = set(dct[key]) s.update(val) dct[key] = s else: dct[key] = val The problem is that I both need to remove duplicates and retain insertion order like list.append().

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Re: [Python-ideas] [Python-Dev] Adding a "sysconfig" module in the stdlib
by Tarek Ziadé 09 May '09

09 May '09

2009/5/8 Jeffrey Yasskin <jyasskin(a)gmail.com>: > > I'm +1 to the idea of a sysconfig module (by whatever name). I > believe, however, that we should be able to generate the module as > part of the build process instead of having it look up values from the > Makefile. Like, constants at the top of the module, generated at built time ? Tarek -- Tarek Ziadé | http://ziade.org

1 0

str.format utility function
by Dag Moxnes 08 May '09

08 May '09

Hi list, I'm sorry if this has been discussed before, but I did not find any references. I've been playing abit with the new str.format function. I really like the syntax and simplicity. However, when simply printing named variables in locals() or a class, I quite common use-case, I find it a bit too complicated with the **: "Local variable var1 is %(var1)s" % locals() vs "Local variable var1 is {var1}".format(**locals()) and "Instance variable var2 is %(var2)s" % self.__dict__ vs "Instance variable var2 is {var2}" % **self.__dict__ Therefore I have made myself a utility funcion: def easyformat(s, data): try: return s.format(**data) except TypeError: return s.format(**data.__dict__) so that I can do the following: "Local variable var1 is {var1}".format(**locals()) and "Instance variable var2 is %(var2)s" % self Should a function similar to this (maybe with a better name) be included included in some standard library? -Dag _________________________________________________________________ Få mer ut av Windows Live™ med Internet Explorer® 8. http://microsoft.no/ie

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Re: [Python-ideas] Add OrderedSet now that OrderedDict is in collections
by Arnaud Delobelle 08 May '09

08 May '09

On 8 May 2009, at 15:23, Mart Sõmermaa wrote: > On Fri, May 8, 2009 at 4:14 PM, Arnaud Delobelle <arnodel(a)googlemail.com > > wrote: >> 2009/5/8 Mart Sõmermaa <mrts.pydev(a)gmail.com>: >>> As Multiset is arguably quite useless[...] >> >> Arguably, it is far from useless. > > Can you perhaps provide a use case where a list (an "ordered > multiset") does not suffice? I implemented a unification algorithm that needed multisets to work in O(n^2). -- Arnaud

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Re: [Python-ideas] [Value Returning Threard]
by yoav glazner 07 May '09

07 May '09

> > > >Please provide more explanation for why the currently available features > >are insufficient. Note that what you're asking for would change the > >semantics of Python at a very deep level and will almost certainly be > >rejected in its present form. > -- > >Aahz (aahz(a)pythoncraft.com) <*> > http://www.pythoncraft.com/ > I'm no python expert but i had to do a stress test on a libary. (checking thread safety) here is the code (we soe absraction): def testMultiThread(): global resultDict resultDict = {} def testFuncThread(func): global resultDict if func(): resultDict[func] = 'Passed' else: resultDict[func] = 'Falied' thread.start_new(testFuncThread,(Test1,)) thread.start_new(testFuncThread,(Test2,)) thread.start_new(testFuncThread,(Test3,)) while (len(resultDict) < 3): time.sleep(5) return resultDict #here i did something else such as logging and returning True or False Maybe there is a better way for doing this? If we had something like i suggested (with .value or not) def testMultiThread(): resultDict = {} resultDict[Test1]= thread.startValueReturningThread(Test1) resultDict[Test1]= thread.startValueReturningThread(Test2) resultDict[Test1]= thread.startValueReturningThread(Test3) return resultDict #or again, pharsing the result...

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[Value Returning Threard]
by yoav glazner 06 May '09

06 May '09

Hi all, My Idea is to have a value returning Thread. I'll explain by example. <pycode> def foo(): time.sleep(20) return 'bar' value = thread.startValueReturningThread(foo) #i need a better name for the function...) #here we do some work mg = moonGravity() mg.disable() #now we need the value that foo returned print value #this would be blocking untill foo is done! </pycode> This feature should provide a way to increase performance when possible with simple syntax. What do you think?

8 8

New list methods
by Zac Burns 06 May '09

06 May '09

I would like to see the following methods added to lists... rindex : Return first index of value from the right rremove: Return first occurence of value from the right. -- Zachary Burns (407)590-4814 Aim - Zac256FL Production Engineer (Digital Overlord) Zindagi Games

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keywording prohibited
by spir 06 May '09

06 May '09

Hello, I have noticed a rather strong and nearly systematic opposition to (new) keywords. Cannot really figure out why. Would someone clearly expose the reasoning behind keeping the keyword set as small as possible? (I thought at not preventing users to use the same words as names, but this reason does not seem to hold. On the contrary: non-keyword builtins bite painfully!) Could not find references on the topic -- probably because a search containing "keyword" returns loads of unrelated stuff. Denis ------ la vita e estrany

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Python-ideas May 2009