Pythonic way of saying 'at least one of a, b, or c is in some_list'

cbrown at cbrownsystems.com cbrown at cbrownsystems.com
Thu Oct 28 18:33:29 CEST 2010


On Oct 28, 9:23 am, John Posner <jjpos... at optimum.net> wrote:
> On 10/28/2010 12:16 PM, cbr... at cbrownsystems.com wrote:
>
> > It's clear but tedious to write:
>
> > if 'monday" in days_off or "tuesday" in days_off:
> >      doSomething
>
> > I currently am tending to write:
>
> > if any([d for d in ['monday', 'tuesday'] if d in days_off]):
> >      doSomething
>
> > Is there a better pythonic idiom for this situation?
>
> Clunky, but it might prompt you to think of a better idea: convert the
> lists to sets, and take their intersection.
>
> -John

I thought of that as well, e.g.:

if set(["monday,"tuesday']).intersection(set(days_off)):
    doSomething

but those extra recasts to set() make it unaesthetic to me; and worse

if not set(["monday,"tuesday']).isdisjoint(set(days_off)):
    doSomething

is bound to confuse most readers.

Cheers - Chjas



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