Basic example
Input
['apple', 'fig', 'banana']
Output
['fig', 'apple', 'banana']
Lengths are 5, 3, 6. Sorted ascending by length yields ['fig', 'apple', 'banana'].
Full lesson preview
Sort words by length using a lambda key
Sort a list of words by their length using a lambda as the key.
Python practice8 minFunctions as Objects (Lambda, Map/Filter)BeginnerLast updated March 20, 2026
Problem statement
Given a list of strings, return a new list with the same strings sorted by their length in ascending order. Use a lambda expression as the key to sorted(). The sort should be stable, so words with the same length keep their original relative order.
Task
Use sorted() with a lambda key to order words by length while preserving stability for ties.
Examples
Input format
A single argument: a list of strings, e.g. ['a', 'bb', 'ccc'].
Output format
A list of strings sorted by length, e.g. ['a', 'bb', 'ccc'].
Constraints
Do not modify the input list in-place; return a new list. Use a lambda with the key parameter of sorted().
Samples
Sample 1
Input
['cat', 'elephant', 'dog']
Output
['cat', 'dog', 'elephant']
Lengths are 3, 8, 3. Stable sort preserves original relative order for 'cat' and 'dog'.