Python-ideas May 2009

python-ideas@python.org

74 participants
41 discussions

by Konrad Delong

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

11 years

Add __nonzero__ to threading.Event

by Floris Bruynooghe

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

11 years

Add OrderedSet now that OrderedDict is in collections

by Mart Sõmermaa

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().

11 years

Re: [Python-ideas] [Python-Dev] Adding a "sysconfig" module in the stdlib

by Tarek Ziadé

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

11 years

str.format utility function

by Dag Moxnes

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

11 years

Re: [Python-ideas] Add OrderedSet now that OrderedDict is in collections

by Arnaud Delobelle

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

11 years

Re: [Python-ideas] [Value Returning Threard]

by yoav glazner

> > > >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...

11 years, 1 month

[Value Returning Threard]

by yoav glazner

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?

11 years, 1 month

New list methods

by Zac Burns

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

11 years, 1 month

keywording prohibited

by spir

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

11 years, 1 month

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Python-ideas May 2009