Chunk a List into Batcheseasy

Chunk a List into Batches

easy Python for AI 10–15 min

NumPy allowed · plain Python earns 10 bonus points

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Partition a flat list into fixed-size batches -- the standard pattern used in LLM prompt batching, database bulk insertion, and mini-batch gradient descent.

Related Skills

Language Fundamentals

Task

Implement chunk_list(items, chunk_size): partition items into sublists of length chunk_size. The final chunk contains the remaining elements if len(items) is not evenly divisible. Raise ValueError if chunk_size <= 0. If items is empty, return [].

Function Signature

chunk_list(items: list, chunk_size: int) -> list[list]

Examples

Example 1: Uneven List Length
Input: items = [1, 2, 3, 4, 5, 6, 7]
chunk_size = 3
Output: [[1, 2, 3], [4, 5, 6], [7]]

Example 2: Exact Multiple Length
Input: items = [10, 20, 30, 40]
chunk_size = 2
Output: [[10, 20], [30, 40]]

Constraints

Libraries are allowed; a plain-Python solution earns 10 bonus points.
Must raise ValueError if chunk_size is less than or equal to 0.
The last chunk may contain fewer elements than chunk_size.
Empty input list returns [].

Python3Saved ✓

def chunk_list(items: list, chunk_size: int) -> list[list]:

"""Split a list into consecutive chunks of at most chunk_size length.

The final chunk may be smaller if len(items) is not divisible by

chunk_size. Raises ValueError if chunk_size <= 0. Empty list returns []."""

# Your implementation here

pass

Case 1: Uneven List Length

Input: items = [1, 2, 3, 4, 5, 6, 7]
chunk_size = 3

Expected: [[1, 2, 3], [4, 5, 6], [7]]

Case 2: Exact Multiple Length

Input: items = [10, 20, 30, 40]
chunk_size = 2

Expected: [[10, 20], [30, 40]]