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format-literals (UP030)#

Derived from the pyupgrade linter.

Fix is sometimes available.

What it does#

Checks for unnecessary positional indices in format strings.

Why is this bad?#

In Python 3.1 and later, format strings can use implicit positional references. For example, "{0}, {1}".format("Hello", "World") can be rewritten as "{}, {}".format("Hello", "World").

If the positional indices appear exactly in-order, they can be omitted in favor of automatic indices to improve readability.


"{0}, {1}".format("Hello", "World")  # "Hello, World"

Use instead:

"{}, {}".format("Hello", "World")  # "Hello, World"