Updates all values by applying a callback function to each value.

说明

public void Ds\Map::apply ( callable $callback )

Updates all values by applying a callback function to each value in the map.

参数

callback

mixed callback ( mixed $key , mixed $value )

A callable to apply to each value in the map.

The callback should return what the value should be replaced by.

返回值

没有返回值。

范例

Example #1 Ds\Map::apply() example


<?php
$map = new \Ds\Map(["a" => 1, "b" => 2, "c" => 3]);
$map->apply(function($key, $value) { return $value * 2; });

print_r($map);
?>

以上例程的输出类似于：

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

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

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

)