itertools.count(x)
count(10) –> 10 11 12 13 14 …
itertools.cycle(x)
cycle(‘ABCD’) –> A B C D A B C D …
itertools.repeat(x)
repeat(10, 3) –> 10 10 10
itertools.combinations(x)
returns possible orderings of input, in sorted order, no repeated elements (order matters and will not be repeated)
itertools.permutations(x)
returns all possible orderings of input, no repeated elements (order does not matter and will be repeated in different orders)