array_udiff

Definition and usage

array_udiff() function is used to compare the key values ​​of two (or more) arrays and return the difference set.

Note: This function uses a user-defined function to compare key values!

The function compares the key values ​​of two (or more) arrays and returns an array of differences that include all key values ​​in the array being compared ( array1 ) but not in any other parameter array ( array2 or array3 , etc.).

Example

Example 1

Compare the key values ​​of two arrays (using user-defined functions to compare key values) and return the difference:

 <?php
function myfunction ( $a , $b )
{
if ( $a === $b )
  {
  return 0 ;
  }
  return ( $a > $b ) ? 1 : - 1 ;
}

$a1 = array ( "a" => "red" , "b" => "green" , "c" => "blue" ) ;
$a2 = array ( "a" => "blue" , ​​"b" => "black" , "e" => "blue" ) ;

$result = array_udiff ( $a1 , $a2 , "myfunction" ) ;
print_r ( $result ) ;
?>

Try it yourself

Example 2

Compare the key values ​​of three arrays (using user-defined functions to compare key values) and return the difference:

 <?php
function myfunction ( $a , $b )
{
if ( $a === $b )
  {
  return 0 ;
  }
  return ( $a > $b ) ? 1 : - 1 ;
}

$a1 = array ( "a" => "red" , "b" => "green" , "c" => "blue" , ​​"yellow" ) ;
$a2 = array ( "A" => "red" , "b" => "GREEN" , "yellow" , "black" ) ;
$a3 = array ( "a" => "green" , "b" => "red" , "yellow" , "black" ) ;

$result = array_udiff ( $a1 , $a2 , $a3 , "myfunction" ) ;
print_r ( $result ) ;

?>

Try it yourself