setsuch

Setsuch is a term used in certain programming languages and mathematical discussions to denote an operation that builds a subset from a collection by selecting elements that satisfy a given condition. The name derives from the phrase “set such that,” commonly used in mathematical notation and set-builder concepts.

Formally, if S is a domain and P is a predicate that maps elements of S to a boolean value, setsuch(S, P) yields the subset { x in S | P(x) }. In many languages this concept is implemented as a higher-order function or operator that filters a collection according to a predicate. In this sense setsuch is closely related to the filter function and, in more declarative languages, to set-builder or comprehension constructs.

Usage and examples vary by language, but the core idea is consistent. For example, setsuch([1, 2, 3, 4], x => x % 2 == 0) would produce [2, 4]. In a typed functional language, setsuch might require a function of the element type that returns a boolean, and the result would be a subset of the original collection’s type. In database-inspired domains, a similar operation appears as a constraint-based selection that yields rows satisfying a predicate.

Origin and status: setsuch is not a standardized operator and appears mainly in informal discussions, tutorials, or domain-specific languages. It serves to illustrate the parallel between mathematical set-builder notation and practical subset selection in programming.

See also: filter, set-builder notation, list comprehension, predicate.