php中计算二维数组中某一元素之和

 <meta charset="utf-8">

<?php
$ar = array(
    2 => array(
        &#39;catid&#39; => &#39;6&#39;,
		&#39;cat&#39; => &#39;dd&#39;,
        &#39;catdir&#39; => &#39;1522332388000&#39;,//2018-03-29 22:06:28
    ),
    6=> array(
        &#39;catid&#39; => &#39;5&#39;,
		&#39;cat&#39; => &#39;dd&#39;,
        &#39;catdir&#39; => &#39;1522329351000&#39;//2018-03-29 21:15:51
    ),
    7=> array(
        &#39;catid&#39; => &#39;4&#39;,
		&#39;cat&#39; => &#39;ddfgd&#39;,
        &#39;catdir&#39; => &#39;1522328237000&#39;//2018-03-29 20:56:15
    ),
    9=> array(
        &#39;catid&#39; => &#39;3&#39;,
		&#39;cat&#39; => &#39;dd&#39;,
        &#39;catdir&#39; => &#39;1522327772000&#39;//2018-03-29 20:49:32
    ),
    10=> array(
        &#39;catid&#39; => &#39;2&#39;,
		&#39;cat&#39; => &#39;dvvd&#39;,
        &#39;catdir&#39; => &#39;1522325351000&#39;//2018-03-29 20:09:11
    ),
    5 => array(
        &#39;catid&#39; => &#39;1&#39;,
		&#39;cat&#39; => &#39;ddfgd&#39;,
        &#39;catdir&#39; => &#39;1522323606000&#39;,//2018-03-29 19:40:06
    ),

);

echo array_sum(array_map(create_function(&#39;$val&#39;, &#39;return $val["catid"];&#39;), $ar));

?>

[0] => array(5) {
      ["id"] => string(2) "11"
      ["name"] => string(5) "1.jpg"
      ["suffix"] => string(3) "jpg"
      ["url"] => string(29) "./Uploads/1/5292f55d208e8.jpg"
      ["size"] => string(6) "715895"
    }
    [1] => array(5) {
      ["id"] => string(2) "12"
      ["name"] => string(22) "minisite数据库.docx"
      ["suffix"] => string(4) "docx"
      ["url"] => string(30) "./Uploads/1/5292f5606a52c.docx"
      ["size"] => string(5) "16667"
    }