How to find most common element in a list of list?

Question

I understand

a = max(set(lst), key=lst.count)

will derive most common element in a list

but how do you derive most common element

Answer 1

You could use Counter to find the most common element, and chain to iterate through the elements of the list of lists:

from collections import Counter
from itertools import chain

print Counter(val for val in chain.from_iterable(lst)).most_common(1)