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To: python-list@python.org
From: Peter Otten <__peter__@web.de>
Subject: Re: my favorite line of py code so far
Date: Sat, 09 Nov 2013 08:12:25 +0100
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Xref: csiph.com comp.lang.python:58906

Peter Cacioppi wrote:

> my fav so far is this
> 
> _ = lambda c : lambda x : c(*x)
> 
> c can be any calleable and x any iterable, but I tend to use it with a
> class, and then map _(class) over the result of a zip.
> 
> It must be in the library somewhere, but I haven't found it. I'm never
> sure what to call it, so I just reroll it into _ as needed. It's pretty
> easy for me to remember, but I'll probably tattoo it on my chest just in
> case.

You mean

>>> class P:
...     def __init__(self, x, y):
...             self.x = x
...             self.y = y
...     def __repr__(self):
...             return "Point(x={0.x}, y={0.y})".format(self)
... 
>>> P(1, 2)
Point(x=1, y=2)
>>> _ = lambda c: lambda x: c(*x)
>>> list(map(_(P), zip([1,2,3], [6, 5, 4])))
[Point(x=1, y=6), Point(x=2, y=5), Point(x=3, y=4)]

? While the obvious approach would be

>>> [P(*args) for args in zip([1,2,3], [6, 5, 4])]
[Point(x=1, y=6), Point(x=2, y=5), Point(x=3, y=4)]

there is also itertools.starmap():

>>> from itertools import starmap
>>> list(starmap(P, zip([1,2,3], [6, 5, 4])))
[Point(x=1, y=6), Point(x=2, y=5), Point(x=3, y=4)]