PHP | array_diff_ukey() Function

The array_diff_ukey() function is an inbuilt function in PHP. It is used to compares the key two or more arrays using a user-defined function, and return an array, which is array1 and its not present any others array2, array3 or more…

Syntax:

array_diff_ukey($array1, $array2, $array3..., arr_diffukeyFunction)

Parameters Used:
This function accepts minimum three parameters and all three parameter is mandatory and the other is optional. The parameters are described below:

1. $array1(mandatory):
   The array will be compared with other arrays.(such that array compare from array1).
2. $array2(mandatory):

   The array Compared with the first array.

3. $array3(Optional):

   The array Compared with the first array.

4. arr_diffukeyFunction(mandatory):

   It is Required user-defined function. A string that defines a callable comparison function.
   The comparison function returns an integer than 0 if the first argument is than the second argument.

Return Value:
Returns an array containing the entries from array1 that are not present in other arrays such as:-(arra2, arra3, arar4….more). If all values are present in other arrays the function return NULL. The return value type is an array.
Example 1:

Input: 
$arr1 = array("one"=>"C Program", "two"=>"PHP Program", "three"=>"Java Program ");
$arr2 = array("one"=>"Java Program", "two"=>"C++ Program", "six"=>"Java Program");

Output: 
Array
(
    [three] => Java Program 
)

Explanation: First two values of arr1 are matched with arr2 and last value 
             not matched so the function returns last value.

Example 2:

Input: 
$arr1=array("one"=>"C Program", "two"=>"PHP Program", "three"=>"Java Program ");
$arr2=array("one"=>"Java Program", "two"=>"C++ Program", "three"=>"Java Program");

Output: 
Array
(
)

Explanation: All values are matched with arr2 so function return null values.

Let’s take an example for understand the array_diff_ukey() Function.

• Program 1 : Taking two array (array1 and array2) and using user-defined key comparison function (diffukeyFunction).

  Simple solution in PHP language :

  <?php
  
  // Program of array_diff_ukey function in PHP
  
  function arr_diffukeyFunction($one, $two)
  {
      if ($one === $two) {
          return 0;
      }
      return ($one > $two) ? 1 : -1;
  }
  
  // Driver Code
  
  $arr1 = array(
      "one" => "C Program",
      "two" => "PHP Program",
      "three" => "Java Program "
  );
  $arr2 = array(
      "one" => "Java Program",
      "two" => "C++ Program",
      "six" => "Java Program"
  );
  
  $result = array_diff_ukey($arr1, $arr2, "arr_diffukeyFunction");
  print_r($result);
  ?>
  Output:

  Array
  (
      [three] => Java Program 
  )
  

• Program 2 : Take three array (array1, array2 and arra3) and using user-defined key comparison function (diffukeyFunction).

  <?php
  
  // Program of array_diff_ukey function in PHP
  
  function arr_diffukeyFunction($one, $two)
  {
      if ($one === $two) {
          return 0;
      }
      return ($one > $two) ? 1 : -1;
  }
  
  // Driver Code
  
  $arr1 = array(
      "one" => "C Program",
      "two" => "PHP Program",
      "three" => "Java Program "
  );
  $arr2 = array(
      "one" => "XML Program",
      "two" => "C++ Program",
      "four" => "CSS Program"
  );
  $arr3 = array(
      "five" => "MVC Program",
      "six" => "C# Program",
      "one" => "ASP .NET Program"
  );
  
  $result = array_diff_ukey($arr1, $arr2, $arr3, "arr_diffukeyFunction");
  print_r($result);
  ?>
  Output:

  Array
  (
      [three] => Java Program 
  )
  

• Program 3 : Return Null if all values are matched in other arrays

  <?php
  
  // Program of array_diff_ukey function in PHP
  function arr_diffukeyFunction($one, $two)
  {
      if ($one === $two) {
          return 0;
      }
      return ($one > $two) ? 1 : -1;
  }
  
  // Driver Code
  $arr1 = array(
      "one" => "C Program",
      "two" => "PHP Program"
  );
  $arr2 = array(
      "one" => "Java Program",
      "two" => "C++ Program"
  );
  
  $result = array_diff_ukey($arr1, $arr2, "arr_diffukeyFunction");
  print_r($result);
  ?>

  Output:

  Array
  (
  )
  

• Program 4 : If we take only one array (array1) and using user-defined key comparison function (diffukeyFunction)There are no output and its gives “RUNTIME ERROR” warning message.

  <?php
  
  //Program of array_diff_ukey function in PHP
  
  function arr_diffukeyFunction($one, $two)
  {
      if ($one === $two) {
          return 0;
      }
      return ($one > $two) ? 1 : -1;
  }
  
  // Driver Code
  
  $arr1 = array(
      "one" => "C Program",
      "two" => "PHP Program",
      "three" => "Java Program "
  );
  
  //take only one array
  
  $result = array_diff_ukey($arr1, "arr_diffukeyFunction");
  print_r($result);
  ?>

  Output:

  No Output

  Warning:

  PHP Warning:  array_diff_ukey(): at least 3 parameters are required,
  2 given in /home/c0177af9f69e897ad93cc9855a9ae415.php on line 23