python list of lists to single list code example

Example 1: python flatten list

itertools.chain.from_iterable(factors)

Example 2: two lists into one list of tules

>>> list_a = [1, 2, 3, 4]
>>> list_b = [5, 6, 7, 8]
>>> list(zip(list_a, list_b))
[(1, 5), (2, 6), (3, 7), (4, 8)]