Dustan DustanGroups at gmail.com
Mon Oct 29 22:00:12 EDT 2007

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On Oct 29, 5:57 pm, GHZ <geraint.willi... at gmail.com> wrote:
> Is this the best way to test every item in a list?

No.

The biggest problem is, obviously, you don't take advantage of
builtins any() and all(), or write corresponding short-circuiting
versions for python versions before 2.5.

The second problem is you build an entire list that gets disposed of
just as quickly. The third problem is you use lambda, which makes your
call to map() time inefficient as well as space inefficient. Both of
these problems can be fixed by using generator expressions.

> def alltrue(f,l):
>     return reduce(bool.__and__,map(f,l))
>
> def onetrue(f,l):
>     return reduce(bool.__or__,map(f,l))
>
>
>
> >>> alltrue(lambda x:x>1,[1,2,3])
> False

>>> all(x>1 for x in [1,2,3])
False

> >>> alltrue(lambda x:x>=1,[1,2,3])
> True

>>> all(x>=1 for x in [1,2,3])
True

> Thanks

HTH

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