PHP array_udiff_uassoc() Function
Quick summary: The PHP array_udiff_uassoc() function computes the difference of arrays using user-defined callbacks for both value and key comparison.
PHP array_udiff_uassoc() Syntax
array_udiff_uassoc(array $array, array ...$arrays, callable $value_compare_func, callable $key_compare_func): arrayPHP
PHP array_udiff_uassoc() Basic examples
function valCmp($a,$b){ return $a <=> $b; }
function keyCmp($a,$b){ return strcmp($a,$b); }
$a=['a'=>1,'b'=>2];
$b=['a'=>2];
print_r(array_udiff_uassoc($a,$b,'valCmp','keyCmp'));PHP
Output:
Array ( [a] => 1 [b] => 2 )Uses custom comparison for both keys and values.
PHP array_udiff_uassoc() Real-world usage
PHP array_udiff_uassoc() Edge cases
array_udiff_uassoc($a,$b,null,null);PHP
Output:
WarningBoth callbacks must be valid callables.
PHP array_udiff_uassoc() Common mistakes
Incorrect callback order
Value comparison callback must come before key comparison callback.
Incorrect
array_udiff_uassoc($a,$b,'keyCmp','valCmp');Correct
array_udiff_uassoc($a,$b,'valCmp','keyCmp');Provide value comparison function first, then key comparison.
PHP array_udiff_uassoc() Frequently Asked Questions
What does array_udiff_uassoc() do?
Computes array difference with user-defined comparison for values and keys.
Use case?
Fully customizable diff.
Callbacks required?
Yes, for values and keys.
Common mistake?
Incorrect callback signatures.
Return type?
Array.
Performance?
Slower due to callbacks.
Safe?
Yes.
Alternative?
array_udiff_assoc().
Flexible?
Highly.
Used in advanced logic?
Yes.
Best practice?
Keep callbacks efficient.
Handles keys and values?
Yes.