I want to stress that in the user function, you do need to return either a 1 or a -1 properly; you cannot simply return 0 if the results are equal and 1 if they are not.
The following code is incorrect:
<?php
function myfunction($v1,$v2)
{
if ($v1===$v2)
{
return 0;
}
return 1;
}
$a1=array(1, 2, 4);
$a2=array(1, 3, 4);
print_r(array_uintersect($a1,$a2,"myfunction"));
?>
This code is correct:
<?php
function myfunction($v1,$v2)
{
if ($v1===$v2)
{
return 0;
}
if ($v1 > $v2) return 1;
return -1;
}
$a1=array(1, 2, 4);
$a2=array(1, 3, 4);
print_r(array_uintersect($a1,$a2,"myfunction"));
?>
array_uintersect
(PHP 5, PHP 7)
array_uintersect — Computes the intersection of arrays, compares data by a callback function
Description
array_uintersect
( array
$array1
, array $array2
[, array $...
], callable $value_compare_func
) : arrayComputes the intersection of arrays, compares data by a callback function.
Parameters
-
array1 -
The first array.
-
array2 -
The second array.
-
value_compare_func -
The 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. Note that before PHP 7.0.0 this integer had to be in the range from -2147483648 to 2147483647.
Return Values
Returns an array containing all the values of array1
that are present in all the arguments.
Examples
Example #1 array_uintersect() example
<?php
$array1 = array("a" => "green", "b" => "brown", "c" => "blue", "red");
$array2 = array("a" => "GREEN", "B" => "brown", "yellow", "red");
print_r(array_uintersect($array1, $array2, "strcasecmp"));
?>
The above example will output:
Array
(
[a] => green
[b] => brown
[0] => red
)
See Also
- array_intersect() - Computes the intersection of arrays
- array_intersect_assoc() - Computes the intersection of arrays with additional index check
- array_uintersect_assoc() - Computes the intersection of arrays with additional index check, compares data by a callback function
- array_uintersect_uassoc() - Computes the intersection of arrays with additional index check, compares data and indexes by separate callback functions
add a note
User Contributed Notes 3 notes
Nate at RuggFamily dot com ¶
12 years ago
rob dot c dot ruiz at gmail dot com ¶
10 months ago
When trying to do a case insensitive comparison between arrays of words, the strcasecmp function works very nicely with this one like so:
$arr1 = array('blue', 'green', 'red');
$arr2 = array('BLUE', 'Purple', 'Red');
$loose_matches = array_uintersect($arr1, $arr2, 'strcasecmp');
print_r($loose_matches) // array('blue', 'red');
Hayley Watson ¶
1 year ago
As for the other "compare function" callbacks, the return value from the callback function doesn't need to be -1, 0, or 1.
cmp($a,$b) just needs to be <0, =0, or >0 depending on whether $a<$b, $a=$b, or $a>$b.
