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Fri May 7 16:37:33 CEST 2010 · https://mail.python.org/pipermail/python-dev/2010-May/099981.html

Howdy all -

I have an app where I am using functools.partial to bundle up jobs to
do, where a job is defined as a callable + args. In one case, I wanted
to keep track of whether I had previously seen a job, so I started
putting them into a set... only to find out that partials never test
equal to each other:

>>> import operator
>>> from functools import partial
>>> p1 = partial(operator.add)
>>> p2 = partial(operator.add)
>>> p1 == p2
False
>>> seen = set();seen.add(p1)
>>> p2 in seen
False

I created a subclass of functools.partial that provides appropriate
__eq__ and __hash__ methods, so that this works as expected. I called
the subclass a Job:
>>> j1 = Job(operator.add)
>>> j2 = Job(operator.add)
>>> j1 == j2
True
>>> seen = set();seen.add(j1)
>>> j2 in seen
True
>>> j1 is j2
False

While I was at it, I also added a nice repr. Would this group be
interested in a patch, or is this not interesting?

Thanks,

Van

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Showing content from https://mail.python.org/pipermail/python-dev/2010-May/099981.html below:

[Python-Dev] Possible patch for functools partial