Search a sequence for its minimum and stop as soon as the lowest possible value is found

Peter Otten __peter__ at web.de
Sun Jan 8 06:24:04 EST 2017


Paul Rubin wrote:

> Paul Rubin <no.email at nospam.invalid> writes:
>> seems to work, but is ugly.  Maybe there's something better.
> 
>     def minabs2(xs):
>         def z():
>             for x in xs:
>                 yield abs(x), x
>                 if x==0: break
>         return min(z())[1]
> 
> is the same thing but a little bit nicer.

Yes, that's another variant of the decorate/undecorate approach combined 
with Wolfgang's local take_until(). The generalized form that cannot rely on 
the sequence items being orderable would be

firstitem = operator.itemgetter(0)


def stopmin_paul(items, *, key, stop):
    def take_until():
        for item in items:
            k = key(item)
            yield k, item
            if k <= stop:
                break
    return min(take_until(), key=firstitem)[1]




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