snakecase

Snake_case is a naming convention in which all letters are lowercase and spaces are replaced by underscores to separate words. A typical example is user_id or parse_input. The style avoids spaces and capitalization, relying on underscores to delineate boundaries. In many guidelines, identifiers should not start with a digit, and consecutive underscores are discouraged unless they have a specific meaning. ASCII letters are normally used, with non-Latin characters generally avoided in core identifiers.

Snake_case is widely used in languages and ecosystems such as Python, Ruby, Rust, and in many configuration files and database schemas. It is often preferred for variables, function names, and file names. By contrast, other naming schemes include camelCase or PascalCase, where capitalization indicates word boundaries, and kebab-case, which uses hyphens and is common in URLs and some file names.

Examples: parse_input, user_id, get_elapsed_time. For constants, some projects use SCREAMING_SNAKE_CASE (all caps with underscores).

Advantages include readability and compatibility with ASCII. Disadvantages include longer identifiers and potential conflicts with language rules about digits or underscores. There are tools to convert between conventions and linters that enforce style.

Historically, snake_case gained prominence in Python and Ruby and has since become a common default in several languages. It remains a standard choice for codebases and configuration alike when lowercase with underscores is preferred.