php判断数组有关问题

本帖最后由 hxlb520 于 2014-09-19 08:53:23 编辑 我想在foreach()循环中只显示没有下级的大栏目（例如只显示代码中的大栏目一,大栏目四），有下级栏目的不显示 ，如何判断呢？

cid=栏目ID，name=栏目名称，parent_cid=子栏目的上级栏目ID

{"seller_cat":[
{"cid":"1","name":"大栏目一","parent_cid":"0"},
{"cid":"2","name":"大栏目二","parent_cid":"0"},
{"cid":"3","name":"子栏目二","parent_cid":"2"},
{"cid":"4","name":"子栏目三","parent_cid":"2"},
{"cid":"5","name":"大栏目三","parent_cid":"0"},
{"cid":"6","name":"子栏目一","parent_cid":"5"},
{"cid":"7","name":"大栏目四","parent_cid":"0"}
]}}
------解决思路----------------------
类方法，可以参考下。

$a = json_decode($s);<br />$ar = array();<br />foreach($a->seller_cat as $t) {<br />  if($t->parent_cid == 0 && ! array_filter($a->seller_cat, array(new T($t->cid), 'filter')))<br />    $ar[] = $t->name;<br />}<br />print_r($ar);<br />class T {<br />        private $cid;<br /><br />        function __construct($cid) {<br />                $this->cid = $cid;<br />        }<br /><br />        function filter($v) {<br />                return $v->parent_cid == $this->cid;<br />        }<br />}

------解决思路----------------------
foreach($a->seller_cats->seller_cat as $t) {
  if($t->parent_cid == 0 && ! array_filter($a->seller_cats->seller_cat, array(new T($t->cid), 'filter')))
    $ar[] = $t->name;
}