list.extend and list comprehension

Question

When I need to add several identical items to the list I use list.extend:

a = [\'a\', \'b\', \'c\']
a.extend([\'d\']*3)

Result

Answer 1

An itertools approach:

import itertools

def flatten(it):
    return itertools.chain.from_iterable(it)

pairs = [['a',2], ['b',2], ['c',1]]
flatten(itertools.repeat(item, times) for (item, times) in pairs)
# ['a', 'a', 'b', 'b', 'c']