Chunk a list in Python

Batching a list into fixed-size pieces - a staple for pagination and APIs.

def chunk(items, size):
    if size < 1:
        raise ValueError("size must be positive")
    return [items[i:i + size] for i in range(0, len(items), size)]

How it works

1. Validates that the chunk size is positive.
2. Slices the list every size elements inside a list comprehension.
3. Returns the slices as a list of chunks.

Keywords and builtins used here

• chunk
• def
• for
• if
• len
• raise
• range
• return

The run, in numbers

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Type this snippet

Step 4 of 10 in Collections, step 26 of 72 in Language basics.

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