(PECL ds >= 1.0.0)
Ds\Vector::map — Returns the result of applying a callback to each value.
Returns the result of applying a callback function to
each value in the vector.
callback
A callable to apply to each value in the vector.
The callable should return what the new value will be in the new vector.
The result of applying a callback to each value in
the vector.
Note:
The values of the current instance won't be affected.
Example #1 Ds\Vector::map() example
<?php
$vector = new \Ds\Vector([1, 2, 3]);
print_r($vector->map(function($value) { return $value * 2; }));
print_r($vector);
?>
以上例程的输出类似于：
Ds\Vector Object
(
[0] => 2
[1] => 4
[2] => 6
)
Ds\Vector Object
(
[0] => 1
[1] => 2
[2] => 3
)