Itertools takewhile method explained

Itertools takewhile makes an iterator that returns elements from the iterable as long as the predicate is true.

import itertools
#we first produce a sequence of numbers stepped by 2
#next we take elements of this sequence while the element is smaller than 11
print list(itertools.takewhile(lambda x: x < 11, itertools.count(0,2)))

[0, 2, 4, 6, 8, 10]