php--------递归函数

Posted 2020-10-23 切切歆语

array_walk 有个原生递归函数 array_walk_recursive($arr, ‘function‘, ‘words‘)，但是 array_map 却没有对应的递归函数 array_map_recursive，

我们可以自定义一个：

function array_map_recursive($filter, $data) 
{
    $result = array();
    foreach ($data as $key => $val) 
    {
        $result[$key] = is_array($val)
         ? array_map_recursive($filter, $val)
         : call_user_func($filter, $val);
    }
 
    return $result;
}

应用举例：

$arr = array(
    ‘a‘ => ‘2‘,
    ‘b‘ => array(
        ‘cc‘ => ‘wen‘,
        ‘dd‘ => ‘jian‘,
        ‘ee‘ => ‘bao‘
    )
);
 
function func_a($value)
{
    $value .= ‘_AAA‘;
    return $value;
}
 
var_dump($arr);
 
$arr = array_map_recursive(‘func_a‘, $arr);
 
var_dump($arr);

其实吧，完全可以用 array_walk_recursive() 函数 实现该功能，如下代码所示：

$arr = array(
    ‘a‘ => ‘2‘,
    ‘b‘ => array(
        ‘cc‘ => ‘wen‘,
        ‘dd‘ => ‘jian‘,
        ‘ee‘ => ‘bao‘
    )
);
 
function func_b(&$value)
{
    $value .= ‘_AAA‘;
}
 
var_dump($arr);
 
array_walk_recursive($arr, ‘func_b‘);
 
var_dump($arr);

输出：

 

array (size=2)
  ‘a‘ => string ‘2‘ (length=1)
  ‘b‘ => 
    array (size=3)
      ‘cc‘ => string ‘wen‘ (length=3)
      ‘dd‘ => string ‘jian‘ (length=4)
      ‘ee‘ => string ‘bao‘ (length=3)

 

array (size=2)
  ‘a‘ => string ‘2_AAA‘ (length=5)
  ‘b‘ => 
    array (size=3)
      ‘cc‘ => string ‘wen_AAA‘ (length=7)
      ‘dd‘ => string ‘jian_AAA‘ (length=8)
      ‘ee‘ => string ‘bao_AAA‘ (length=7)