PHP array_udiff_assoc() Function

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# PHP array_udiff_assoc() Function

Complete PHP Array Reference

## 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

From http://www.w3schools.com (Copyright Refsnes Data)