Help With filter().

[Remco Gerlich]

EricIDLE <grayson-wilson at home.com> wrote in comp.lang.python:
> I Still Dont Get It. Could you explain it in simpiler terms?

Filter 'filters' a list, it lets through only those elements of a list for
which some condition is true.

For instance, say you have a list of numbers 0 to 20 (range(21)), and you
want to have only those that are divisable by three.

Then you make a small function that is true when a number is divisable by
three:

def divisable_by_three(x):
   if x % 3 == 0:
      return 1
   else:
      return 0

Now you can use that to filter the list:

filter(divisable_by_three, range(21))

That should return [0, 3, 6, 9, 12, 15, 18].

-- 
Remco Gerlich