how to unpack a list of lists into a single list in python code example

Example 1: python flat list from list of list

flat_list = [item for sublist in l for item in sublist]

#which is equivalent to this 
flat_list = []
for sublist in l:
    for item in sublist:
        flat_list.append(item)

Example 2: flatten a list of list python

# idiomatic python

# using itertools
import itertools

list_of_list = [[1, 2, 3], [4, 5], [6]]
chain = itertools.chain(*images)

flattened_list = list(chain)
# [1, 2, 3, 4, 5, 6]