Strstartswithprefix

Strstartswithprefix is a string operation used in programming to determine whether a given string begins with a specified prefix. It returns a boolean value: true if the string starts with the prefix, and false otherwise. The term is commonly used in documentation or pseudocode to describe prefix matching across languages.

In real languages, the concept appears as a function or method name such as startsWith, startsWithPrefix, or strstartswithprefix. Variants may accept optional parameters to constrain the check to a substring, typically providing the string to test, the prefix, and optional start and end indices. A prefix argument may be a single string, or, in some APIs, a collection of prefixes.

Algorithmically, the operation compares characters of the prefix with the corresponding characters at the start of the tested string, stopping at the first mismatch or when the prefix completes. Time complexity is generally O(p), with p being the prefix length; memory usage is O(1) beyond input storage. Some implementations apply optimizations for common prefixes or use specialized data structures in broader contexts.

Edge cases include an empty prefix, which usually yields true, and case sensitivity, which depends on language defaults. If a start or end boundary is provided, the check applies to the designated substring. Unicode handling and locale considerations can affect results, particularly for case-insensitive or locale-aware comparisons.

See also: Python's str.startswith, JavaScript's String.prototype.startsWith, and Java's String.startsWith.