how to combine strings in a list that have same length and create lists of list in python

Question

I have a list of strings. Based on the length of each string, I need to group them in one list. finally one list should contain all the lists.

Example:

input

in=['the', 'way', 'you', 'see', 'people', 'is', 'the', 'way', 'you', 'treat', 'them', 'and', 'the', 'way', 'you', 'treat', 'them', 'is', 'what', 'they', 'become']

output

expected_out=[['is'],['and', 'see', 'the', 'way', 'you'], ['them', 'they', 'what'], ['treat'], ['become', 'people']]

Answer 1

Don't know if this is the best way to do it, but it's the first thing that came to my mind:

from collections import defaultdict

len2words = defaultdict(set)

for word in input_list:
    len2words[len(word)].add(word)

output = [list(len2words[key]) for key in sorted(len2words.keys())]