predicateswhere

Predicateswhere is a term used in computer science to describe an operation that filters elements of a collection by applying one or more predicates. The name merges predicates—logical conditions that evaluate to true or false—and the where clause common in SQL to select rows that satisfy a condition. Although informal, predicateswhere appears in documentation and discussions as a convenient shorthand for composing predicate-based filters.

Implementation and usage: In practice, a predicateswhere operation can be a higher-order function, a filter-like method, or a DSL operator that accepts a predicate or a conjunction of predicates and returns the subset that satisfies them. Predicates can be combined with logical AND, OR, and NOT, and they can be parameterized or curried to form reusable filters. Some libraries expose a predicateswhere combinator to build complex criteria from simpler predicates.

Relation to related concepts: Predicateswhere is related to predicate logic, SQL where clauses, and filter operations in functional programming. It is commonly used in data processing pipelines, query construction, data validation, and API parameter filtering.

Examples: Given a dataset of records, predicateswhere might select those where age > 18 and status is "active." In a streaming context, it can be evaluated lazily to avoid materializing intermediates.

Limitations: The term is informal and its meaning can vary across languages and libraries. Performance depends on how predicates are evaluated and whether filtering can be optimized by the data source.

See also: Predicate logic, filter, where clause, query DSL, combinators.