Heap's algorithm permutation generator

Question

I need to iterate over permutations of a tuple of integers. The order has to be generated by swapping a pair of elements at each step.

I found the Wikipedia article

Answer 1

The easiest way to get the permutations of a list would be the permutations function, in the itertools module. So, if the algorithm is not binding, I would go with this:

from itertools import permutations

a = [1,2,3,4]
for item in permutations(a):
    print item