Chunk a list
Input
chunk_iterable([1,2,3,4,5], 2)
Output
[[1, 2], [3, 4], [5]]
The list is split into chunks of size 2. The final chunk contains the leftover element.
Full lesson preview
Chunk an iterable into fixed-size blocks
Split any iterable into consecutive fixed-size chunks. The last chunk may be smaller.
Python practice16 minModules & Standard LibraryIntermediateLast updated March 23, 2026
Problem statement
Write chunk_iterable(iterable, size) which takes any iterable and an integer chunk size > 0 and returns a list of lists. Each inner list should contain up to size elements, preserving the original order. The final chunk may have fewer than size elements if there aren't enough remaining. The function should accept any iterable (lists, strings, generators, range, etc.).
Task
Implement chunk_iterable(iterable, size) returning a list of lists, where each inner list is a chunk of up to size elements taken from the iterable in order.
Examples
Input format
Two arguments: an iterable and a positive integer size, e.g., chunk_iterable([1,2,3], 2)
Output format
A list of lists representing consecutive chunks
Constraints
- size is a positive integer (>=1).
- Do not assume the input is a sequence; support any iterable.
- Use only the Python standard library (itertools is allowed).
Samples
Sample 1
Input
chunk_iterable('abcdef', 3)
Output
[['a', 'b', 'c'], ['d', 'e', 'f']]
Strings are iterables; chunks are lists of characters.