PHP Reference

Quick Reference

The PHP array_diff_uassoc() function compares the keys 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.

Only the keys are compared. Not the values.

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

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

$result = array_diff_uassoc($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 5] => Maserati )

Syntax

array_diff_ukey(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.