How to remove duplicate values ​​from php array

php Array method to remove duplicate values: 1. Use the "array_unique" function to delete duplicates from a one-dimensional array; 2. Delete duplicates from a two-dimensional array through the "assoc_unique" and "array_unique_fb" methods.

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php Array deduplication (one-dimensional array and two-dimensional array Dimensional array)

Removal of duplicate items in the array

Duplicate items in one-dimensional array:

Use the array_unique function. The usage examples are as follows:

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

The result is as follows: Array ([0] => apple [1] => banana [2] => pear [4] => wail [5] => watermalon ).

Duplicates of two-dimensional arrays:

We will discuss two-dimensional arrays in two situations. One is because the value of a certain key name cannot be repeated, and duplicates are deleted; the other is Because the internal one-dimensional arrays cannot be exactly the same, and duplicates are deleted, the following example illustrates:

           Because the value of a certain key name cannot be repeated, delete duplicates

<?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(&#39;id&#39; => 123, &#39;name&#39; => &#39;张三&#39;),
            array(&#39;id&#39; => 123, &#39;name&#39; => &#39;李四&#39;),
            array(&#39;id&#39; => 124, &#39;name&#39; => &#39;王五&#39;),
            array(&#39;id&#39; => 125, &#39;name&#39; => &#39;赵六&#39;),
            array(&#39;id&#39; => 126, &#39;name&#39; => &#39;赵六&#39;)
            );
            $key = &#39;id&#39;;
            assoc_unique(&$aa, $key);
            print_r($aa);
            ?>

The display result is:

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 Because the internal one -dimensional array cannot be exactly the same, delete the duplicate item

<?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(&#39;id&#39; => 123, &#39;name&#39; => &#39;张三&#39;),
            array(&#39;id&#39; => 123, &#39;name&#39; => &#39;李四&#39;),
            array(&#39;id&#39; => 124, &#39;name&#39; => &#39;王五&#39;),
            array(&#39;id&#39; => 123, &#39;name&#39; => &#39;李四&#39;),
            array(&#39;id&#39; => 126, &#39;name&#39; => &#39;赵六&#39;)
            );
            $bb=array_unique_fb($aa);
            print_r($bb)
            ?>

Display results:

r

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