filter

Note

This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information.

Returns a ImmVector containing the values of the current ImmVector that meet a supplied condition

public function filter(
  (function(Tv): bool) $callback,
): ImmVector<Tv>;

filter()'s result contains only values that meet the provided criterion; unlike map(), where a value is included for each value in the original ImmVector.

Guide

• Examples

Parameters

• (function(Tv): bool) $callback

Returns

• ImmVector<Tv> - An ImmVector containing the values after a user-specified condition is applied.

Examples

See Vector::filter for usage examples.