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Thu Nov 27 14:21:37 EST 2003 · https://mail.python.org/pipermail/python-dev/2003-November/040477.html

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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