(PHP 5, PHP 7, PHP 8)
array_udiff_assoc — Computes the difference of arrays with additional index check, compares data by a callback function
Computes the difference of arrays with additional index check, compares data by a callback function.
Note: Please note that this function only checks one dimension of a n-dimensional array. Of course you can check deeper dimensions by using, for example,
array_udiff_assoc($array1[0], $array2[0], "some_comparison_func");.
arrayThe first array.
arraysArrays to compare against.
value_compare_funcThe comparison function must return an integer less than, equal to, or greater than zero if the first argument is considered to be respectively less than, equal to, or greater than the second.
Returning non-integer values from the comparison
function, such as float, will result in an internal cast to
int of the callback's return value. So values such as
0.99 and 0.1 will both be cast to an
integer value of 0, which will compare such values as equal.
The sorting callback must handle any value from any array in any order, regardless of the order they were originally provided. This is because each individual array is first sorted before being compared against other arrays. For example:
<?php
$arrayA = ["string", 1];
$arrayB = [["value" => 1]];
// $item1 and $item2 can be any of "string", 1 or ["value" => 1]
$compareFunc = static function ($item1, $item2) {
$value1 = is_string($item1) ? strlen($item1) : (is_array($item1) ? $item1["value"] : $item1);
$value2 = is_string($item2) ? strlen($item2) : (is_array($item2) ? $item2["value"] : $item2);
return $value1 <=> $value2;
};
?>
array_udiff_assoc() returns an array
containing all the values from array
that are not present in any of the other arguments.
Note that the keys are used in the comparison unlike
array_diff() and array_udiff().
The comparison of arrays' data is performed by using an user-supplied
callback. In this aspect the behaviour is opposite to the behaviour of
array_diff_assoc() which uses internal function for
comparison.
Example #1 array_udiff_assoc() example
<?php
class cr {
private $priv_member;
function __construct($val)
{
$this->priv_member = $val;
}
static function comp_func_cr($a, $b)
{
if ($a->priv_member === $b->priv_member) return 0;
return ($a->priv_member > $b->priv_member)? 1:-1;
}
}
$a = array("0.1" => new cr(9), "0.5" => new cr(12), 0 => new cr(23), 1=> new cr(4), 2 => new cr(-15),);
$b = array("0.2" => new cr(9), "0.5" => new cr(22), 0 => new cr(3), 1=> new cr(4), 2 => new cr(-15),);
$result = array_udiff_assoc($a, $b, array("cr", "comp_func_cr"));
print_r($result);
?>The above example will output:
Array
(
[0.1] => cr Object
(
[priv_member:private] => 9
)
[0.5] => cr Object
(
[priv_member:private] => 12
)
[0] => cr Object
(
[priv_member:private] => 23
)
)
In our example above you see the "1" => new cr(4)
pair is present in both arrays and thus it is not in the output from the
function.