Difference between array_udiff_assoc() and array_diff_assoc()
- array_udiff_assoc(): Compares the DATA with the user supplied callback function
- array_diff_assoc(): Compares the INDEX with the user supplied callback function
(PHP 5, PHP 7)
array_udiff_assoc — Computes the difference of arrays with additional index check, compares data by a callback function
$array1
, array $array2
[, array $...
], callable $value_compare_func
)Computes the difference of arrays with additional index check, compares data by a callback function.
Note: Please note that this function only checks one dimension of a n-dimensional array. Of course you can check deeper dimensions by using, for example, array_udiff_assoc($array1[0], $array2[0], "some_comparison_func");.
array1The first array.
array2The second array.
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.
array_udiff_assoc() returns an array
containing all the values from array1
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 $priv_member;
function cr($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.
Difference between array_udiff_assoc() and array_diff_assoc()
- array_udiff_assoc(): Compares the DATA with the user supplied callback function
- array_diff_assoc(): Compares the INDEX with the user supplied callback function
What is the difference between array_udiff_assoc and array_diff_uassoc?