求高手一个算法
有两个二维数组
- PHP code
<!-- Code highlighting produced by Actipro CodeHighlighter (freeware) http://www.CodeHighlighter.com/ --> $a=array( array('id'=>'1','name'=>'a','url'=>'c'), array('id'=>'2','name'=>'aa','url'=>'cc'), array('id'=>'3','name'=>'aaa','url'=>'ccc') ); $b=array( array('name'=>'aa','url'=>'cc'), array('name'=>'a','url'=>'c') );
如何能够得到array('id'=>'3','name'=>'aaa','url'=>'ccc')呢?意思就是说,比较两个数组中除了id的项,如果数组a中的值在数组b中不存在,则筛选出来,不希望使用嵌套foreach,每个数组中都有好几万条记录,所以效率是个问题。请教各位,还望有思路的朋友赐教。
------解决方案--------------------
- PHP code
$t=array(); foreach($b as $vl) $t[$vl['name'].$vl['url']]=$vl; foreach($a as $k=>$v) if(!$t[$v['name'].$v['url']]) unset($a[$k]); print_r($a); <br><font color="#e78608">------解决方案--------------------</font><br>
------解决方案--------------------
isset 判断一个值是否在列表中
并无所谓是键还是值,也无所谓你的数据是如何组织的
总之,他是在列表中查询,最坏的情况就是检索到列表的最后一个元素
其实 isset 与 in_array 是相似的
就有人在我的某个类似问题中(使用了 in_array)提出了质疑
很简单,仅就算法而言,并不能因为是php内部实现的,就不计算在内
哈希表的性能优于线性表,但在时间复杂度上还是一样的
当然并不排除我的高中学历影响了对理论知识的理解

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Configuring the session lifecycle in PHP can be achieved by setting session.gc_maxlifetime and session.cookie_lifetime. 1) session.gc_maxlifetime controls the survival time of server-side session data, 2) session.cookie_lifetime controls the life cycle of client cookies. When set to 0, the cookie expires when the browser is closed.


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