Python built-in collection functions

Iterate over a list

for item in [1, 2, 3]:
    print item

Length/size/count

len([1, 2, 3])

Map. Keep in mind the result of map is Iterable

fun = lambda x: x * 2
map(fun, [1,2,3])

Filter. Returns a filter object

even = lambda x: x%2 == 0
filter(even, [1,2,3])