使用できますitertools.chain.from_iterable
:
>>> from itertools import chain
>>> list(chain.from_iterable(animals))
['dog', 'cat', 'mouse', 'bird']
またはネストされたlist comprehension
:
>>> [anim for item in animals for anim in item]
['dog', 'cat', 'mouse', 'bird']
小さなリストの場合はリスト内包版を使用し、それ以外の場合は を使用しますitertools.chain.from_iterable
。
>>> animals = [('dog', 'cat'), ('mouse', 'bird')]
>>> %timeit list(chain.from_iterable(animals))
100000 loops, best of 3: 2.31 us per loop
>>> %timeit [anim for item in animals for anim in item]
1000000 loops, best of 3: 1.13 us per loop
>>> animals = [('dog', 'cat'), ('mouse', 'bird')]*100
>>> %timeit list(chain.from_iterable(animals))
10000 loops, best of 3: 31.5 us per loop
>>> %timeit [anim for item in animals for anim in item]
10000 loops, best of 3: 73.7 us per loop
>>> animals = [('dog', 'cat'), ('mouse', 'bird')]*1000
>>> %timeit list(chain.from_iterable(animals))
1000 loops, best of 3: 296 us per loop
>>> %timeit [anim for item in animals for anim in item]
1000 loops, best of 3: 733 us per loop