(PECL ds >= 1.0.0)
Ds\Map::map — Returns the result of applying a callback to each value
Returns the result of applying a callback function to
each value of the map.
callback
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.
The result of applying a callback to each value in
the map.
Note:
The keys and values of the current instance won't be affected.
Example #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);
?>
以上例程的输出类似于：
(
[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
)
)