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array_uintersect

(PHP 5, PHP 7)

array_uintersectComputes the intersection of arrays, compares data by a callback function

Description

array_uintersect ( array $array , array ...$arrays , callable $value_compare_func ) : array

Computes the intersection of arrays, compares data by a callback function.

Parameters

array

The first array.

arrays

Arrays to compare against.

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.

callback ( mixed $a, mixed $b ) : int

Return Values

Returns an array containing all the values of array 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

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User Contributed Notes 3 notes

up
10
Nate at RuggFamily dot com
13 years ago
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"));
?>
up
1
rob dot c dot ruiz at gmail dot com
2 years 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');
up
1
Hayley Watson
2 years 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.
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