Batch a stream with a size limit

Python data engineering interview problem. Difficulty: intermediate. Pattern: Streaming. About 15 minutes. Part of the Pro drill bank.

An event stream should be flushed to disk in batches of at most N items so a crash only loses one batch.

Split a sequence into batches of a given size.

Requirements

• Every item appears in exactly one batch.
• The last batch may be shorter.

Constraints

• items: the stream as a list.
• size: max batch length.
• size is at least 1.

Examples

Input: batched([1, 2, 3, 4, 5], 2) Output: [[1, 2], [3, 4], [5]] This input follows the stated rules and produces this output.

Topics: lakebench, python, generators.

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