Ds\Deque::filter
(PECL ds >= 1.0.0)
Ds\Deque::filter — Creates a new deque using a callable to determine which values to include
說明
Creates a new deque using a callable to determine which values to include.
參數
- 
callback
- 
        Optional callable which returns trueif the value should be included,falseotherwise.If a callback is not provided, only values which are true(see converting to boolean) will be included.
返回值
    A new deque containing all the values for which
    either the callback returned true, or all values that
    convert to true if a callback was not provided.
  
範例
示例 #1 Ds\Deque::filter() example using callback function
<?php
$deque = new \Ds\Deque([1, 2, 3, 4, 5]);
var_dump($deque->filter(function($value) {
    return $value % 2 == 0;
}));
?>
以上例程的輸出類似於:
object(Ds\Deque)#3 (2) {
  [0]=>
  int(2)
  [1]=>
  int(4)
}
示例 #2 Ds\Deque::filter() example without a callback function
<?php
$deque = new \Ds\Deque([0, 1, 'a', true, false]);
var_dump($deque->filter());
?>
以上例程的輸出類似於:
object(Ds\Deque)#2 (3) {
  [0]=>
  int(1)
  [1]=>
  string(1) "a"
  [2]=>
  bool(true)
}