php 数组去重

一维数组的重复项：

      使用array_unique函数即可，使用实例如下：

              <?php
                  $aa=array("apple","banana","pear","apple","wail","watermalon");
                  $bb=array_unique($aa);
                  print_r($bb);
               ?>

      结果如下：Array ( [0] => apple [1] =>banana [2] => pear [4] => wail [5]=> watermalon ) 。

二维数组的重复项：

     对于二维数组咱们分两种情况讨论，一种是因为某一键名的值不能重复，删除重复项；另一种因为内部的一维数组不能完全相同，而删除重复项，下面举例说明：

           ㈠因为某一键名的值不能重复，删除重复项

          <?php
           function assoc_unique($arr, $key)
            {
              $tmp_arr = array();
              foreach($arr as $k => $v)
             {
                if(in_array($v[$key],$tmp_arr))//搜索$v[$key]是否在$tmp_arr数组中存在，若存在返回true
               {
                  unset($arr[$k]);
               }
             else {
                 $tmp_arr[] = $v[$key];
               }
             }
           sort($arr); //sort函数对数组进行排序
           return $arr;
           }

           $aa = array(
           array('id' => 123, 'name' =>'张三'),
           array('id' => 123, 'name' =>'李四'),
           array('id' => 124, 'name' =>'王五'),
           array('id' => 125, 'name' =>'赵六'),
           array('id' => 126, 'name' =>'赵六')
           );
           $key = 'id';
           assoc_unique(&$aa, $key);
           print_r($aa);
           ?>

     显示结果为：Array ( [0] => Array ( [id] =>123 [name] => 张三 ) [1] => Array ([id] => 124 [name] => 王五 ) [2]=> Array ( [id] => 125 [name]=> 赵六 ) [3] => Array ( [id]=> 126 [name] => 赵六 ) )

       ㈡因内部的一维数组不能完全相同，而删除重复项

           <?php
           function array_unique_fb($array2D){
                foreach ($array2D as $v){
                    $v = join(",",$v); //降维,也可以用implode,将一维数组转换为用逗号连接的字符串
                    $temp[] = $v;
                }
                $temp =array_unique($temp);   //去掉重复的字符串,也就是重复的一维数组
               foreach ($temp as $k => $v){
                   $temp[$k] = explode(",",$v);  //再将拆开的数组重新组装
               }
               return $temp;
           }

           $aa = array(
           array('id' => 123, 'name' =>'张三'),
           array('id' => 123, 'name' =>'李四'),
           array('id' => 124, 'name' =>'王五'),
           array('id' => 123, 'name' =>'李四'),
           array('id' => 126, 'name' =>'赵六')
           );
           $bb=array_unique_fb($aa);
           print_r($bb)
           ?>

         显示结果：Array ( [0] => Array ( [0] =>123 [1] => 张三 ) [1] => Array ( [0]=> 123 [1] => 李四 ) [2]=> Array ( [0] => 124 [1]=> 王五 ) [4] => Array ( [0]=> 126 [1] => 赵六 ))