<?php
function key_comp_func($a,$b)
{
if ($a===$b)
{
return 0;
}
return ($a>$b)?1:-1;
}

$a1=array("red","green","blue","yellow");
$a2=array("red","green","white");

$result=array_diff_ukey($a1,$a2,"key_comp_func");
print_r($result);
?>

Run example »

Definition and Usage

The array_diff_ukey() function compares the keys of two (or more) arrays, and returns the differences.

Note: This function uses a user-defined function to compare the keys!

This function compares the keys of two (or more) arrays, and return an array that contains the entries from array1 that are not present in array2.

Syntax

array_diff_ukey(array1,array2,array3...,myfunction);

Parameter	Description
array1	Required. The array to compare from
array2	Required. An array to compare against
array3,...	Optional. More arrays to compare against
myfunction	Required. A string that define a callable comparison function. The comparison function must return an integer <, =, or > than 0 if the first argument is <, =, or > than the second argument

Technical Details

Return Value:	Returns an associative array containing the entries from array1 that are not present in any of the other arrays
PHP Version:	5.1+

More Examples

Example 1

Compare the keys of two associative arrays (use a user-defined function to compare the keys), and return the differences:

<?php
function key_comp_func($a,$b)
{
if ($a===$b)
{
return 0;
}
return ($a>$b)?1:-1;
}

$a1=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow");
$a2=array("c"=>"red","d"=>"green","e"=>"blue");

$result=array_diff_ukey($a1,$a2,"key_comp_func");
print_r($result);
?>

Run example »

PHP Array Reference