strformat

Strformat is a string formatting operation used in programming to produce a new string by substituting placeholders in a template with the values of provided expressions. The function is often called strformat or similar, and may be implemented as a function or method. It is distinct from simple concatenation and typically supports type conversion and formatting directives.

Most implementations use a format string with placeholders. Placeholder syntax varies: positional indices like {0}, {1}; named placeholders like {name}; or percent/printf-style specifiers such as %d, %s. The call signature usually takes a template and a list of arguments, possibly with keyword arguments, and returns the formatted result. Features commonly include alignment, width, precision, numeric and date formatting, and locale awareness. Some languages require escaping of braces to include literal braces.

Examples: many languages have analogous constructs. In Python, "Hello, {0}".format("Alice") yields "Hello, Alice". In other ecosystems, a similar mechanism is provided under names like String.format, format, or fmt::format. Some libraries provide a function named strformat as a wrapper to implement a formatting routine. Performance and safety considerations include avoiding untrusted format strings which may cause errors or vulnerabilities; prefer compile-time format checks when available.

See also: string interpolation, printf, format strings. History: fusing placeholders with format specifiers has deep roots in C-era printf-style formatting; modern languages introduced more flexible, type-safe variants. The term strformat is less formal as a language-agnostic name and is often used as a descriptive alias rather than a formal standard.