[Python-Dev] python-dev Summary for 10-16-2003 through
11-15-2003[draft]
Brett C.
bac at OCF.Berkeley.EDU
Thu Nov 27 14:21:37 EST 2003
Raymond Hettinger wrote:
>>If you ever wanted to have the power of list comprehensions but
>
> without
>
>>the overhead of generating the entire list you have Peter Norvig
>>initially and then what seems like the rest of the world for generator
>>expressions.
>
>
> [possibly mangled sentence doesn't make sense]
>
Or me not typing as fast as my brain is working. There is a critical
"to thank" missing from that sentence.
>
>
>
>>After the addition of the 'key' argument to list.sort(), people began
>
> to
>
>>clamor for list.sort() to return self. Guido refused to do give in,
>
> so
>
>>a compromise was reached. 'list' now has a class method named
>
> 'sorted'.
>
>> Pass it a list and it will return a *copy* of that list sorted.
>
>
>
> [Add]
> What makes a class method so attractive is that the argument need not be
> a list, any iterable will do. The return value *is* of course a list.
>
> By returning a list instead of None, list.sorted() can be used as an
> expression instead of a statement. This makes it possible to use it as
> an argument in a function call or as the iterable in a for-loop::
>
> # iterate over a dictionary sorted by key
> for key, value in list.sorted(mydict.iteritems()):
>
Changed it to state that it takes an iterable. Didn't add the full-on
tutorial on use, though. Chances are people who read the Summary know
Python well enough to realize the method's use.
>
>
>
>>As an interim solution, itertools grew a new function: tee. It takes
>
> in
>
>>an iterable and returns two iterators which independently iterate over
>>the iterable.
>
>
> [replace] two
> [with] two or more
>
>
Done.
>
>
>>The point that operator.isMappingType is kind of broken came up. Both
>>Alex and Raymond Hettinger would not mind seeing it disappear. No one
>>objected. It is still in CVS at the moment, but I would not count on
>
> it
>
>>necessarily sticking around.
>
>
> ["It's not quite dead yet" ;-) Actually, there may be a way to
> partially fix-it so that it won't be totally useless].
>
>
Fixed.
>
>
>>There was a new built-in named reversed(), and all rejoiced.
>
>
> [And much flogging of the person who proposed it]
>
>
Fixed. =)
>
>
>>Straight from the function's doc string: "reverse iterator over values
>>of the sequence". `PEP 322`_ has the relevant details on this toy.
>
>
> [Replace] toy
> [With] major technological innovation of the first order
> [Or just] builtin.
>
>
I went with the latter since I need to keep some journalistic integrity
and thus not be too biased. =)
>
>
>
>>Sets now at blazing C speeds!
>
>
> [Looks like a certain parroteer will soon by eating pie!]
>
>
>
> Another fine summary.
> Thanks for the good work.
>
You're quite welcome.
Happy Thanksgiving, Raymond (and everyone else out there).
-Brett
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