(PECL ds >= 1.0.0)
Ds\Map::filter — Creates a new map using a callable to determine which pairs to include
Creates a new map using a callable to determine which pairs to include.
callback Optional callable which returns true if the pair should be included, false otherwise.
If a callback is not provided, only values which are true (see converting to boolean) will be included.
A new map containing all the pairs for which either the callback returned true, or all values that convert to true if a callback was not provided.
Example #1 Ds\Map::filter() example using callback function
<?php
$map = new \Ds\Map(["a", "b", "c", "d", "e"]);
var_dump($map->filter(function($key, $value) {
return $key % 2 == 0;
}));
?>The above example will output something similar to:
object(Ds\Map)#3 (3) { [0]=> object(Ds\Pair)#2 (2) { ["key"]=> int(0) ["value"]=> string(1) "a" } [1]=> object(Ds\Pair)#4 (2) { ["key"]=> int(2) ["value"]=> string(1) "c" } [2]=> object(Ds\Pair)#5 (2) { ["key"]=> int(4) ["value"]=> string(1) "e" } }Example #2 Ds\Map::filter() example without a callback function
<?php
$map = new \Ds\Map(["a" => 0, "b" => 1, "c" => true, "d" => false]);
var_dump($map->filter());
?>The above example will output something similar to:
object(Ds\Map)#2 (3) { [0]=> int(1) [1]=> string(1) "a" [2]=> bool(true) }