Substratring

Substratring is a term used in programming and text processing to refer to the operation or family of operations that deal with substrings of a string. It can denote the act of extracting a specific substring, enumerating substrings, or applying transformations to substrings without altering the original string. While not a standardized language feature, it is employed as a convenient umbrella in documentation and discussions about string processing.

Formally, let S be a string over an alphabet. The common variant Substratring(S, i, j) returns the substring of S from index i to j, with indices following a chosen convention (for example, 0-based, half-open intervals). Substratring can also refer to generating the set of all substrings of S, or to filtering substrings by length, content, or other predicates. In practice, systems may implement substring access by copying the selected segment or by creating a non-owning view into S.

Complexity: a single substring operation that copies k characters runs in O(k) time and space. Enumerating all substrings yields O(n^2) substrings for a string of length n; copying them all has total cost O(n^3) characters. More advanced data structures, such as suffix trees or suffix arrays, enable efficient queries for whether a substring exists or for enumerating substrings with certain properties without materializing every substring.

Applications include text search, pattern mining, bioinformatics, and data compression. Example: Substratring("example", 1, 4) yields "xam" under 0-based indexing and half-open intervals.

Status: Substratring is not an official standard term but a descriptive name used in literature and teaching to discuss substring-related operations.