How to remove duplicate values from a multi-dimensional array in PHP

Here is another way. No intermediate variables are saved.

We used this to de-duplicate results from a variety of overlapping queries.

$input = array_map("unserialize", array_unique(array_map("serialize", $input)));

Another way. Will preserve keys as well.

function array_unique_multidimensional($input)
{
    $serialized = array_map('serialize', $input);
    $unique = array_unique($serialized);
    return array_intersect_key($input, $unique);
}

The user comments on the array_unique() documentation have many solutions to this. Here is one of them:

kenrbnsn at rbnsn dot com
27-Sep-2005 12:09

Yet another Array_Unique for multi-demensioned arrays. I've only tested this on two-demensioned arrays, but it could probably be generalized for more, or made to use recursion.

This function uses the serialize, array_unique, and unserialize functions to do the work.

function multi_unique($array) {
    foreach ($array as $k=>$na)
        $new[$k] = serialize($na);
    $uniq = array_unique($new);
    foreach($uniq as $k=>$ser)
        $new1[$k] = unserialize($ser);
    return ($new1);
}

This is from http://ca3.php.net/manual/en/function.array-unique.php#57202.

A very easy and logical way to Unique a multi dimension array is as follows,

If you have array like this:

Array
(
    [Key1] => Array
        (
            [0] => Value1
            [1] => Value2
            [2] => Value1
            [3] => Value3
            [4] => Value1
        )
    [Key2] => Array
        (
            [0] => Value1
            [1] => Value2
            [2] => Value1
            [3] => Value3
            [4] => Value4
        )
)

use foreach to solve this:

foreach($array as $k=>$v){
    $unique=array_unique($v);
    $array[$k]=$unique;
}

it will give you following result:

Array
(
    [Key1] => Array
        (
            [0] => Value1
            [1] => Value2
            [3] => Value3
        )
    [Key2] => Array
        (
            [0] => Value1
            [1] => Value2
            [3] => Value3
            [4] => Value4
        )
)

and if you want to rearrange the order of the keys,

foreach($array as $k=>$v){
    $unique= array_values(array_unique($v));
    $array[$k]=$unique;
}

This operation will give you arranged key values like this:

Array
(
    [Key1] => Array
        (
            [0] => Value1
            [1] => Value2
            [2] => Value3
        )
    [Key2] => Array
        (
            [0] => Value1
            [1] => Value2
            [2] => Value3
            [3] => Value4
        )
)

I hope this will clear everything.

An easy to read solution, probably not the most efficient:

function arrayUnique($myArray){
    if(!is_array($myArray))
        return $myArray;

    foreach ($myArray as &$myvalue){
        $myvalue=serialize($myvalue);
    }

    $myArray=array_unique($myArray);

    foreach ($myArray as &$myvalue){
        $myvalue=unserialize($myvalue);
    }

    return $myArray;

} 

try this solution for (n) Dimensional array with non-restricted length
for example this array

$arr= [
0 => [0=>"a" , 1=>"b" ,  2=>"c" ] ,
1 => [0=>"x" , 1=>"b" , 2=>"a", 3=>"p"],
2=>   [
       [ 
          0=>"y" ,
          1=>"b" ,
          2=> [0=>"x" , 1=>"m" , 2=>"a"]
       ],
       1=>"z" ,
       2=>"v"
       ]
     ];

This would be the solution

$ar2=[];
$ar3=[];
function test($arr){
    
    global $ar2,$ar3;
    if(is_array($arr)){
       return array_map("test",$arr);
    }
    if(!isset($ar2[$arr])){
        $ar2[$arr]=1;
        $ar3[]=$arr;
    }
}
array_map("test",$arr);
print_r($ar3);

Based on the Answer marked as correct, adding my answer. Small code added just to reset the indices-

$input = array_values(array_map("unserialize", array_unique(array_map("serialize", $inputArray))));