PHP array_udiff() function

The array_udiff function compares the values of an array with the values of another array or arrays and returns the difference between them.

It uses a user-defined function to compare the values. It returns an array that contains the values that are present in the first array but not in the rest of the arrays.

What is the syntax of the array_udiff function in PHP?

array_intersect_ukey(array1, array2, array3, ..., myfunction)

Parameters	Details
array1	The first array to compare with other arrays – required
array2	Second array to make a comparison against- required
array3, ...	Further arrays to compare against – optional
user-defined function	User-defined function to compare the keys of arrays. The function must return an integer <, = or > than 0 if the first argument is <, + or > than the second argument.

Examples of the array_udiff function

Example 1. Take two arrays and return the difference using a user-defined function.

<?php
function my_function($x,$y)
{
if ($x==$y)
  {
  return 0;
  }
  return ($x>$y)?1:-1;
}

$array_1=array("a"=>"R","b"=>"G","c"=>"B");
$array_2=array("a"=>"B","b"=>"Bl","e"=>"B");

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

Example 2. Take three arrays and return the difference using a user-defined function.

<?php
function my_function($x,$y)
{
if ($x==$y)
  {
  return 0;
  }
  return ($x>$y)?1:-1;
}

$array_1=array("a"=>"R","b"=>"G","c"=>"B");
$array_2=array("a"=>"B","b"=>"Bl","e"=>"B");
$array_3=array("a"=>"G","b"=>"R","e"=>"Y", "f"=>"Bl");

$result=array_udiff($array_1,$array_2,$array_3,"my_function");
print_r($result);
?>