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batched-without-explicit-strict (B911)

Added in 0.10.0 · Related issues · View source

Derived from the flake8-bugbear linter.

What it does

Checks for itertools.batched calls without an explicit strict parameter.

Why is this bad?

By default, if the length of the iterable is not divisible by the second argument to itertools.batched, the last batch will be shorter than the rest.

In Python 3.13, a strict parameter was added which allows controlling if the batches must be of uniform length. Pass strict=True to raise a ValueError if the batches are of non-uniform length. Otherwise, pass strict=False to make the intention explicit.

Example

import itertools

itertools.batched(iterable, n)

Use instead if the batches must be of uniform length:

import itertools

itertools.batched(iterable, n, strict=True)

Or if the batches can be of non-uniform length:

import itertools

itertools.batched(iterable, n, strict=False)

Known deviations

Unlike the upstream B911, this rule will not report infinite iterators (e.g., itertools.cycle(...)).

Options

References