PHP Reference

Quick Reference

The PHP array_udiff_assoc() function compares the keys/values of two or more arrays, and returns an array of entries from array1 not in the other array(s).

This function uses a user-defined function to compare the keys and values.

Both the keys and values are compared. Both must be a match.

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

$a1 = array('Car 1' => 'Lamborghini', 'Car 2' => 'Alfa Romeo', 'Car 5' => 'Maserati');
$a2 = array('Car 1' => 'Lamborghini', 'Car 2' => 'Ferrari', 'Car 3' => 'Maserati');

$result = array_udiff_assoc($a1, $a2, 'my_function');
print_r($result);
?>

Note

Arrays count starting from zero NOT one. So item 1 is position [0], item 2 is position [1], and item 3 is position [2] … and so on.

Output

Array ( [Car 2] => Alfa Romeo [Car 5] => Maserati )

Syntax

array_udiff_assoc(array1, array2, array3, ..., my_function)

Parameters

ParameterDescription
array1The array to compare from (required)
array2The array to compare against (required)
array3, ...Additional arrays to compare against
my_functionA string that defines a callable comparison function; the comparison function must return an integer <, =, or > than 0 if the first argument is <, =, or > than the second argument (required)

PHP Notes:

  • When using PHP, single or double quotation marks are acceptable and work identically to one another; choose whichever you prefer, and stay consistent
  • Arrays count starting from zero NOT one; so item 1 is position [0], item 2 is position [1], and item 3 is position [2] … and so on

We’d like to acknowledge that we learned a great deal of our coding from W3Schools and TutorialsPoint, borrowing heavily from their teaching process and excellent code examples. We highly recommend both sites to deepen your experience, and further your coding journey. We’re just hitting the basics here at 1SMARTchicken.