Snake case

Snake case is a way of writing phrases without spaces, where spaces are replaced with underscores _, and the words are typically all lower case. It's often stylized as "snake_case" to remind the reader of its appearance.

Snake casing is often used as a variable naming convention. The following names are in snake case: left_shift, bitwise_invert, matrix_transpose.

Note that snake case never contains upper case letters. Sometimes, constants are written in all-uppercase, such as JavaScript's Number.MAX_SAFE_INTEGER. This is not typically considered as snake case. Instead, it is sometimes called screaming snake case.

Snake case is the most popular convention in Python, Rust, and various other languages.

See also