PHP array_uintersect() Function
Quick summary: The PHP array_uintersect() function computes the intersection of arrays using a user-defined comparison function for values.
PHP array_uintersect() Syntax
array_uintersect(array $array, array ...$arrays, callable $value_compare_func): arrayPHP
PHP array_uintersect() Basic examples
function cmp($a, $b){ return $a <=> $b; }
$a = [1,2,3];
$b = [2,3,4];
print_r(array_uintersect($a, $b, 'cmp'));PHP
Output:
Array ( [1] => 2 [2] => 3 )Returns common values using custom comparison.
PHP array_uintersect() Real-world usage
function caseCmp($a,$b){ return strcasecmp($a,$b); }
$a=['Apple','Banana'];
$b=['apple','Orange'];
print_r(array_uintersect($a,$b,'caseCmp'));PHP
Output:
Array ( [0] => Apple )Case-insensitive intersection of string arrays.
PHP array_uintersect() Edge cases
array_uintersect([1,2],[2],null);PHP
Output:
WarningCallback must be a valid callable.
PHP array_uintersect() Common mistakes
Returning boolean from callback
Comparison callback must return integer (<0, 0, >0).
Incorrect
array_uintersect($a,$b,fn()=>true);Correct
array_uintersect($a,$b,fn($x,$y)=>$x<=>$y);Return proper comparison integer.
PHP array_uintersect() Frequently Asked Questions
What does array_uintersect() do?
Computes intersection of arrays using user-defined value comparison.
Use case?
Custom intersection logic.
Callback required?
Yes.
Common mistake?
Incorrect comparison logic.
Return type?
Array.
Performance?
Moderate.
Safe?
Yes.
Alternative?
array_intersect().
Handles keys?
No.
Flexible comparison?
Yes.
Best practice?
Optimize callback.
Used in filtering?
Yes.