[Patches] [ python-Patches-1660179 ] functools.compose to chain functions together

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Thu Feb 15 11:25:28 CET 2007


Patches item #1660179, was opened at 2007-02-15 00:17
Message generated for change (Comment added) made by gbrandl
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Category: Library (Lib)
Group: Python 2.6
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Chris AtLee (catlee)
>Assigned to: Martin v. Löwis (loewis)
Summary: functools.compose to chain functions together

Initial Comment:
The motivation for this patch was to be able to chain together operator.itemgetter objects so that I could sort a list of items that have the form ((a,b), c) by the 'a' or 'b' part of the item.

Sorting by 'b' can be accomplished with:
l.sort(key=compose(itemgetter(1), itemgetter(0)))

compose(itemgetter(1), itemgetter(0)) is equivalent to

def c(v):
    return itemgetter(1)(itemgetter(0)(v))

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>Comment By: Georg Brandl (gbrandl)
Date: 2007-02-15 10:25

Message:
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The patch looks good, is complete (one nit, "Returns" should be "Return"
in the doc) and the functionality belongs into functools.
What do you think, Martin?

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