[Python-Dev] map, filter, zip in future_builtins

Tue Mar 18 22:10:56 CET 2008

On Tue, Mar 18, 2008 at 3:54 PM, David Wolever <wolever at cs.toronto.edu> wrote:
> I'm working on #2171 -- putting map, filter, zip in 2.6's
> future_builtins.
> It has been suggested that it would be simplest to just return
> itertools.(imap, izip, ifilter), which is what py3k/Python/
> bltinmodule.c, revision 61356 did.
>> The advantage of this is that it's really easy and the behaviour
> seems to be identical.
> The disadvantage is that the two aren't identical:
> >>> type(map(lambda x: x, [1, 2, 3])) # Python 3
> <type 'map'>
> >>> type(map(lambda x: x, [1, 2, 3])) == map
> True
>> >>> type(map(lambda x: x, [1, 2, 3])) # Python 2.6, with the patch
> <type 'itertools.imap'>
> >>> type(map(lambda x: x, [1, 2, 3])) == map
> False
>> Recommendations?

Doesn't strike me as a terrible problem.
Why is the latter == failing? What's the different between
type(map(...)) and map?
-- 
--Guido van Rossum (home page: http://www.python.org/~guido/)