Level 1Exercise #23

Group anagrams

Group anagram words while preserving input order within each group.

What you’ll practice

This Level 1 exercise focuses on dictionary grouping in the Core Python curriculum. Solve the challenge prompt above using clear, idiomatic Python and the relevant language or standard-library tools.

Relevant Python reference: collections — Container datatypes.

Sample Test Cases

Example #1

Input:group_anagrams(["eat", "tea", "tan", "ate"])

Output:[['eat','tea','ate'],['tan']]

Reference Solution

Reveal Reference Solution

def group_anagrams(words: list[str]) -> list[list[str]]:
    groups = {}
    for word in words:
        key = ''.join(sorted(word))
        groups.setdefault(key, []).append(word)
    return list(groups.values())

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Group anagrams

What you’ll practice

Sample Test Cases

Further Reading

Reference Solution