Stringformat

Stringformat is a programming concept and feature that allows embedding values into a string template by using placeholders. The template contains fixed text and markers that are replaced with actual data when the string is produced. This enables consistent, locale-aware presentation of numbers, dates, and text.

Placeholders vary by language. Common forms include numbered tokens like {0}, indexed specifiers such as %d, and named tokens like {name}. Examples: In Java, String.format("Score: %d, Name: %s", score, name). In Python, "Score: {score}, Name: {name}". In C#, String.Format("Score: {0}, Name: {1}", score, name). In C, printf("Score: %d, Name: %s", score, name).

Features of stringformat mechanisms include control over alignment and width (for example, right- or left-justified fields), precision for floating-point numbers, and formatting of dates and times. Many languages also support culture- or locale-specific formatting for numbers and dates, and the ability to customize formatting by implementing appropriate interfaces or format specifications.

Origin traces to the printf family in C and to subsequent libraries in other languages that provide dynamic string construction for user interfaces, logs, reports, and messages. In modern code, stringformat facilities are often complemented by performance-conscious approaches such as string builders or by language features that perform interpolation at compile time or runtime more efficiently.

See also: string interpolation, formatting, localization.