Hash maps and sets · routine

Group anagrams

Words are anagrams if they use the same letters: listen and silent. Write anagram_groups(words) returning a list of groups (lists of words, each in original order); the order of the groups does not matter.

Give every word a key that anagrams share — its letters sorted — and group by that key in a dictionary.

right answers
arguments left as they should be

def anagram_groups(words):
    groups = []
    for w in words:
        placed = False
        for g in groups:
            if len(g[0]) == len(w):
                g.append(w)
                placed = True
                break
        if not placed:
            groups.append([w])
    return groups

Run adds print(anagram_groups(["listen", "silent", "cat"])) after your code, to try it.

Stuck on the idea rather than the code? The Choosing a key lesson walks through it.