sort one list using the values from another list
Ron Adam
rrr at ronadam.com
Sun Feb 26 19:22:46 EST 2006
Alex Martelli wrote:
> Ron Adam <rrr at ronadam.com> wrote:
>
>> bearophileHUGS at lycos.com wrote:
>>> Your solution Steven Bethard looks very intelligent, here is a small
>>> speed test, because sorting a list according another one is a quite
>>> common operation.
>>> (Not all solutions are really the same, as Alex has shown).
>> Try this one.
>>
>> def psort10(s1, s2):
>> d = dict(zip(s2,s1))
>> s1[:] = (d[n] for n in sorted(d.keys()))
>>
>> It's faster on my system because d.keys() is already sorted. But that
>> may not be the case on other versions of python.
>
> If there are duplicates in s2, this solution will silently lose some
> items from s1. I would at least include an assert len(s2)==len(d) as
> the second statement to get some insurance that this doesn't occur.
>
>
> Alex
Good point, and a function that only works part time isn't good. ;-)
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