PHP uses the user-defined function array_intersect_ukey() to compare key names

Example

Compare the key names of two arrays (using user custom function to compare key names) and return the intersection:

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

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

$result=array_intersect_ukey($a1,$a2,"myfunction");
print_r($result);
?>

Definition and usage

array_intersect_ukey() function is used to compare the key names of two (or more) arrays and return the intersection.

Note: This function uses a user-defined function to compare key names!

This function compares the key names of two (or more) arrays and returns an intersection array that includes everything in the compared array (array1) and any other parameter arrays. (array2 or array3, etc.).

array3, etc.

Syntax

array_intersect_ukey(array1,array2,array3...,myfunction)

Parameters	Description
array1	Required. The first array to compare with other arrays.
array2	Required. The array to compare to the first array.
array3,...	Optional. Additional array to compare with the first array.
myfunction	Required. A string that defines a callable comparison function. If the first argument is <, =, > and the second argument is, the corresponding comparison function must return an integer of <, =, > 0.

Technical details

Return value:	Returns an intersection array, which contains All keys in the compared array (array1) that are also in any other parameter arrays (array2 or array3, etc.).
PHP version:	5.1.0+

More examples

Examples 1

Compare the key names of the three arrays (use a user-defined function to compare the key names) and return the intersection:

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

$a1=array("a"=>"red","b"=>"green","c"=>"blue");
$a2=array("a"=>"black","b"=>"yellow","d"=>"brown");
$a3=array("e"=>"purple","f"=>"white","a"=>"gold");

$result=array_intersect_ukey($a1,$a2,$a3,"myfunction");
print_r($result);
?>

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