Ds\Map::intersect

(PECL ds >= 1.0.0)

Ds\Map::intersect — Creates a new map by intersecting keys with another map

説明

public Ds\Map::intersect ( Ds\Map $map ) : Ds\Map

Creates a new map containing the pairs of the current instance whose keys are also present in the given map. In other words, returns a copy of the current instance with all keys removed that are not also in the other map.

A ∩ B = {x : x ∈ A ∧ x ∈ B}

注意:

Values from the current instance will be kept.

パラメータ

map

The other map, containing the keys to intersect with.

返り値

The key intersection of the current instance and another map.

See Also

例

例1 Ds\Map::intersect() example

<?php
$a = new \Ds\Map(["a" => 1, "b" => 2, "c" => 3]);
$b = new \Ds\Map(["b" => 4, "c" => 5, "d" => 6]);

var_dump($a->intersect($b));
?>

上の例の出力は、 たとえば以下のようになります。

object(Ds\Map)#3 (2) {
  [0]=>
  object(Ds\Pair)#4 (2) {
    ["key"]=>
    string(1) "b"
    ["value"]=>
    int(2)
  }
  [1]=>
  object(Ds\Pair)#5 (2) {
    ["key"]=>
    string(1) "c"
    ["value"]=>
    int(3)
  }
}