array_udiff in PHP

array_udiff() function is used to compare two or more input arrays, in a user-defined function, and then it returns an array containing the elements from the first array, if the user-defined function allows it.

The user-defined function compares array values, and returns a numeric value, a positive number(1) if the returned array should contain this element, and 0, or a negative number (-1), if not.

Syntax:

array_udiff(array1,array2,array3...,function)

Parameters Description:

array1 : Required. The first array is the array that the others will be compared with
array2 : Required. An array to be compared with the first array
array3 : Optional. An array to be compared with the first array

function : Required. The name of the user-made function

Example:

<?php 
function myfunc($par1,$par2)
{
if($par1===$par2)
{ 
return 0;
}
return 1;
}
$daysarr1 = array( "a"=>"Sunday","b"=>"Monday","c"=>"Tuesday" );
$daysarr2 = array( 1=>"Sunday",2=>"Monday",3=>"Thursday" );
print_r(array_udiff($daysarr1,$daysarr2,"myfunc"));
?>

Output:

Array (
        [c] => Tuesday
       )