Remove Duplicates From Multidimensional Array

In this post, I am going to explain how to remove duplicate values from multidimensional array in PHP. I use array_unique() to get unique but its work on single-dimensional array, not able to work on multidimensional arrays.

You can remove duplicates from the multidimensional array by value in PHP.

I found answers to find a unique multidimensional array after a lot of googling. As a result, we’ll use array serialization for this. Serialization is a technique for storing and transmitting PHP values without compromising their type or structure.

Checkout other tutorial of PHP Array,

• Merge Two Array or Multiple Array in PHP
• How To Convert XML To Associative Array in PHP
• How To Convert XSD into Array Using PHP
• Convert XML to Array in PHP Using XML2Array
• PHP Array Length Tutorial With Example
• How To Add Elements to an Array in PHP?
• Remove Duplicates From Multidimensional Array

array_unique in PHP

The array_unique() function are used to remove duplicate data from given array.

Syntax:
array_unique(array, sorttype)

There are two parameters that will be passed in the array_unique(), first specifying an array that is required and the second is optional specifying the sorting type.

Optional parameters have the following possible values :

• SORT_STRING – Default
• SORT_NUMERIC
• SORT_REGULAR
• SORT_LOCALE_STRING

Remove duplicate values from an array in PHP

Let’s remove duplicate values from an array using PHP array_unique() method.

<?php
$reqArray=array("name"=-->"adam","sub"=>"english","sub"=>"french","sub"=>"english");
echo "<pre>";
print_r(array_unique($reqArray));
?>

The output of array before removing duplicate values from a multi-dimensional array in PHP.

Array
(
    [name] => adam
    [sub] => english
)

PHP Multidimensional Array

$reqArray = array(
      array(
          "name" => "john"
      ),
      array(
          "age" => "12"
      ),
      array(
          "address" => "Delhi"
      ),
      array(
          "name" => "john"
      )

  );

Remove Duplicate Values from Multidimensional Array:

We will follow the following steps to create a PHP function that will remove duplicate values from the multi dimensional array.
Step 1: First we will use serialize() funtion to serialize the array. Then use the map with PHP inbuilt function.
Step 2: use unserialize() function to make the serialized string into a PHP value.

Function to remove duplicated values

$reqArray=array(array(
          "name" => "john"
      ),
      array(
          "age" => "12"
      ),
      array(
          "address" => "Delhi"
      ),
      array(
          "name" => "john"
      )
     );
  $output =  array_map("unserialize", array_unique(array_map("serialize", $reqArray)));
     
  echo "<pre>";print_r($output);
}

The output of the array after removing duplicate values from a multi-dimensional array in PHP.

Output:

Array
(
    [0] => Array
        (
            [name] => john
        )

    [1] => Array
        (
            [age] => 12
        )

    [2] => Array
        (
            [address] => Delhi
        )

)

Example 2

Remove Duplicate values From Multi Array

$reqArray=array( array("name","age"), 
 array("depart","salary"), 
 array("name","empiId"), 
 array("name","age")
);

$output =  array_map("unserialize", array_unique(array_map("serialize", $reqArray)));

echo "<pre>";print_r($output);

The output of array after removing duplicate values from a multi-dimensional array in PHP.

Output:

Array
(
    [0] => Array
        (
            [0] => name
            [1] => age
        )

    [1] => Array
        (
            [0] => depart
            [1] => salary
        )

    [2] => Array
        (
            [0] => name
            [1] => empiId
        )

)

Find the Duplicate values in array using PHP

<?php
$array=array("john","12","john", "13", "12");
$count_array = array_count_values($array);
echo "<pre>"; 
print_r($count_array);
?>

Output:

Array
(
    [john] => 2
    [12] => 2
    [13] => 1
)