How can I print the list [[4],[42],[1,1,1,1], [2,2,2,2,2,2]] as [4,42,1,1,1,1,2,2,2,2,2] in python?

Question

I have to sort the list based on frequency of occurrence and I am trying this way but getting stuck.

Code snippet of the program

Answer 1

import itertools

some_list = [[4], [42], [1, 1, 1, 1], [2, 2, 2, 2, 2, 2]]
flat = list(itertools.chain(*some_list))
print(flat)

Orrrr some black magic:

some_list = [[4], [42], [1, 1, 1, 1], [2, 2, 2, 2, 2, 2]]
flat = sum(some_list, [])
print(flat)