endswithsuffix

Endswithsuffix is a text-processing concept used to describe the operation of determining whether a string ends with a given suffix. It is a common primitive in string handling and appears in many programming languages under names such as endswith, endsWith, hasSuffix, or equivalent suffix-matching functions.

Formally, for a string s of length n and a suffix t of length m, endswithsuffix(s, t) is true if m <= n and the last m characters of s equal t; otherwise it is false. By convention, the empty suffix yields true, since every string ends with the empty string. Comparisons can be case-sensitive or case-insensitive depending on language settings or explicit options.

Variants and considerations include case sensitivity, locale or Unicode normalization, and how to handle prefixes or overlapping patterns. Some languages offer additional parameters, such as starting a search from a specified position, but the core operation remains a suffix check.

Common implementations appear across languages: Python’s str.endswith, JavaScript’s String.endsWith, Java’s String.endsWith, and C#’s String.EndsWith. These functions typically run in time proportional to the length of the suffix and use constant extra space, though implementations may optimize for common suffix lengths or caching.

Applications include file extension validation, URL path matching, command parsing, and filtering or routing logic where a string’s ending determines the action. See also: suffix, substring, prefix, and hasSuffix as related concepts in text processing.