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PHP array_intersect_ukey() Function

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Definition and Usage

The array_intersect_ukey() function compares the keys in two or more arrays, checking for matches, before comparing the keys in a user-defined function, then returns an array with the keys and values from the first array, if the function allows it.

Syntax

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

Parameter Description
array1 Required. The first array is the array that the others will be compared with
array2 Required. An array to be compared with the first array
array3 Optional. An array to be compared with the first array
function Required. The name of the user-made function

Tips and Notes

Tip: You can compare the first array with one array, or as many as you like.

Note: Only the keys have to be the same to get a match, both in the automatic comparison and in the user-defined function.

Example 1

<?php
function myfunction($v1,$v2) 
{
if ($v1===$v2)
	{
	return 0;
	}
if ($v1>$v2)
	{
	return 1;
	}
else
	{
	return -1;
	}
}
$a1=array(0=>"Dog",1=>"Cat",2=>"Horse");
$a2=array(3=>"Rat",1=>"Bird",5=>"Monkey");
print_r(array_intersect_ukey($a1,$a2,"myfunction"));
?>

The output of the code above will be:

Array ( [] => Cat )

Example 2

How to assign more than two arrays to the function

<?php
function myfunction($v1,$v2) 
{
if ($v1===$v2)
	{
	return 0;
	}
if ($v1>$v2)
	{
	return 1;
	}
else
	{
	return -1;
	}
}
$a1=array(0=>"Dog",1=>"Cat",2=>"Horse");
$a2=array(0=>"Rat",1=>"Bird",5=>"Monkey");
$a3=array(6=>"Dog",7=>"Donkey",0=>"Horse");
print_r(array_intersect_ukey($a1,$a2,$a3,"myfunction"));
?>

The output of the code above will be:

Array ( [0] => Dog )

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