On 19-Jun-07, at 10:51 AM, Bill Janssen wrote:
>
> Though, from the standpoint of pragmatism, removing "reduce" from the
> built-in space will break code (*my* code, among others), and leaving
> it in will not affect "purity", as both "map" and "reduce" are being
> left in. So leaving it alone seems the more Pythonic response to me.
map (especially the new iterized version) is a frequently-used
builtin, while reduce is a rarely-used builtin that requires some
head-wrapping. It makes sense to me to move it out of builtins.
To pick a codebase at random (mine):
$ find -name \*.py | xargs wc -l
137952 total
$ pygrep map\( | wc -l
220
$ pygrep imap\( | wc -l
13
$ pygrep reduce\( | wc -l
2
Of the two uses of reduce(), one is in a unittest that should be
using any():
self.assertTrue(not reduce((lambda b1, b2: b1 or b2), ...
and the other is a tricky combination of callable "iterator filters"
that looks something like this:
df = lambda itr: reduce(lambda x, f: f(x), filter_list, itr)
this isn't the clearest piece of code, even with more explanation.
It would require a multi-line inner-function generator to replace
it. I'm have no qualms importing reduce for such uses.
In contrast, partial(), which should have less use as most of the
codebase was written pre-2.5, and requires an import, is used four
times:
$ pygrep partial\( | wc -l
4
-Mike
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