PHP マニュアル: Returns the result of applying a callback to each value

説明

public Ds\Map Ds\Map::map(callable $callback)

Returns the result of applying a callback function to each value of the map.

パラメータ

callback

mixed callback(mixed $key, mixed $value)

A callable to apply to each value in the map.

The callable should return what the key will be mapped to in the resulting map.

戻り値

The result of applying a callback to each value in the map.

注意:
The keys and values of the current instance won't be affected.

例

例1 Ds\Map::map example

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

print_r($map->map(function($key, $value) { return $value * 2; }));
print_r($map);
?>

上の例の出力は、たとえば以下のようになります。

(
    [0] => Ds\Pair Object
        (
            [key] => a
            [value] => 2
        )

    [1] => Ds\Pair Object
        (
            [key] => b
            [value] => 4
        )

    [2] => Ds\Pair Object
        (
            [key] => c
            [value] => 6
        )

)
Ds\Map Object
(
    [0] => Ds\Pair Object
        (
            [key] => a
            [value] => 1
        )

    [1] => Ds\Pair Object
        (
            [key] => b
            [value] => 2
        )

    [2] => Ds\Pair Object
        (
            [key] => c
            [value] => 3
        )

)