Converting a list of tuples into a simple flat list [duplicate]

Answer 1

Use chain.from_iterable, as it avoids unnecessary all-at-once unpacking (which leads to redundant memory consumption) by lazily advancing through list:

>>> import itertools
>>> L = [(1,2), (1,3), (1,4), (1,5), (1,6)]
>>> list(itertools.chain.from_iterable(L))
[1, 2, 1, 3, 1, 4, 1, 5, 1, 6]