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PHP array_udiff_assoc() Function

Definition and Usage

The array_udiff_assoc() function compares two or more arrays, both in a built in function and in a user-made function, and then returns an array containing the elements from the first array, if the functions allow it. The built in function compares the keys. The user-made function compares the values, and returns a numeric value, a positive number (1) if the returned array should contain this element, and 0, or a negative number (-1), if not.

Syntax

array_udiff_assoc(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: For comparison, the key is used in the built-in function and the value is used in the user-made function.

Example

<?php
function myfunction($v1,$v2) 
{
if ($v1===$v2)
	{
	return 0;
	}
return 1;
}
$a1=array("a"=>"Cat","b"=>"Dog","c"=>"Horse");
$a2=array("a"=>"Cat","b"=>"Horse","c"=>"Dog");
print_r(array_udiff_assoc($a1,$a2,"myfunction"));
?>

The output of the code above will be:

Array ( [b] Dog [c] => Horse )

Complete PHP Array Reference