collectionswhere

collectionswhere is an informal term used to describe the operation of selecting elements from a collection that satisfy a given predicate. It is analogous to filtering in functional programming, the SQL WHERE clause, and the Where method found in languages like LINQ. The term is not part of a formal language specification, but it appears in documentation, tutorials, and discussions as a concise way to refer to conditional collection selection.

Origins and usage

The name blends “collection” and “where,” highlighting that the result consists of those elements for which a condition holds. In practice, collectionswhere can be implemented as a function or method that takes a collection and a predicate and returns a new collection containing only the elements that satisfy the predicate. The resulting collection may be a new list, an array, an iterable, or a lazy sequence, depending on the language and implementation.

Syntax and behavior

Common forms are functional-style and method-call styles. Pseudo-code examples include:

- collectionswhere(numbers, n -> n > 10)

- numbers.where(n => n > 10)

Behaviorary considerations include whether evaluation is eager (producing a concrete result immediately) or lazy (producing elements on demand), and whether the result preserves the original collection type.

Relation to other concepts

collectionswhere is related to filtering, selection, and subset construction. It often appears alongside map, reduce, and other higher-order operations in discussions of functional and declarative programming. See also: filter, where (LINQ), SQL WHERE, list comprehension.

Notes

As a term, collectionswhere serves as a descriptive shorthand rather than a standardized keyword in programming languages.