PHP Ds Set reduce()用法及代碼示例

Ds\Set::reduce() 函數可以使用回調函數將集合減少為單個值。

用法

public mixed Ds\Set::reduce( callable $callback [, mixed $initial ] )

Ds\Set::reduce() 函數可以返回最終回調的值。

例子1

<?php  
   $set = new \Ds\Set([10, 20, 30, 40]);  
   echo("The original set elements:\n");  
   print_r($set);  
   
   $func = function($carry, $element) {  
      return $carry * $element;  
   };  
   
   echo("\n The set after reducing to single element:\n");  
   var_dump($set->reduce($func, 10));
?>

例子2

<?php  
   $set = new \Ds\Set([10, 20, 30, 40, 50]);  
   
   echo("The set elements are:\n");  
   print_r($set);  
   
   echo("\n An element after performing operation:\n");  
   
   var_dump($set->reduce(function($carry, $element) {  
      return $carry + $element + 2;  
   }));  
?>