Best way to check if an item is present in a list of lists? [duplicate]

Answer 1

You can do use combination of any, map and chain:

In [19]: example_list = [['aaa'], ['fff', 'gg'], ['ff'], ['', 'gg']]

In [20]: import operator, itertools

In [21]: any(map(operator.not_, itertools.chain(*example_list)))
Out[21]: True

In [22]: example_list = [['aaa'], ['fff', 'gg'], ['ff'], ['not empty', 'gg']]

In [23]: any(map(operator.not_, itertools.chain(*example_list)))
Out[23]: False