Ds\Set::map

(PECL ds >= 1.2.7)

Ds\Set::map — Returns the result of applying a callback to each value

说明

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

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

参数

callback

The callback to apply to each value in the set must have the following signature:

callback(mixed $value): mixed

返回值

Returns a new Ds\Set instance where each value is the result of applying the callback to each value of the set.

示例

示例 #1 Ds\Set::map() example

<?php
$set = new \Ds\Set([1, 2, 3]);

var_dump($set->map(function($value) { return $value * 2; }));
var_dump($set);
?>

以上示例的输出类似于：

object(Ds\Set)#3 (3) {
  [0]=>
  int(2)
  [1]=>
  int(4)
  [2]=>
  int(6)
}
object(Ds\Set)#1 (3) {
  [0]=>
  int(1)
  [1]=>
  int(2)
  [2]=>
  int(3)
}