best way to compare contents of 2 lists?

[bearophileHUGS at lycos.com]

Arnaud Delobelle:
> Thanks to the power of negative numbers, you only need one dict:
>
> d = defaultdict(int)
> for x in a:
>     d[x] += 1
> for x in b:
>     d[x] -= 1
> # a and b are equal if d[x]==0 for all x in d:
> not any(d.itervalues())

Very nice, I'll keep this for future use.
Someday I'll have to study this new new kind of numbers that can
represent borrowed items too.

Bye,
bearophile