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enumerate-for-loop (SIM113)

Added in v0.2.0 · Related issues · View source

Derived from the flake8-simplify linter.

What it does

Checks for for loops with explicit loop-index variables that can be replaced with enumerate().

Why is this bad?

When iterating over a sequence, it's often desirable to keep track of the index of each element alongside the element itself. Prefer the enumerate builtin over manually incrementing a counter variable within the loop, as enumerate is more concise and idiomatic.

Example

fruits = ["apple", "banana", "cherry"]
i = 0
for fruit in fruits:
    print(f"{i + 1}. {fruit}")
    i += 1

Use instead:

fruits = ["apple", "banana", "cherry"]
for i, fruit in enumerate(fruits):
    print(f"{i + 1}. {fruit}")

References