PHP, Structures and Functions of ARRAY

This function returns an ARRAY containing all the entries from $array1 that are not present in any of the other arrays.

This function is like array_diff except the comparison is done on the values instead of the keys.

The $values_compare_func, CALLBACK function, must return an integer less than, equal to, or greater than zero if the first argument is considered to be respectively less than, equal to, or greater than the second.

Prior to PHP 7.0.0 this value is an INTEGER in the range -2147483648 to 2147483647.


<?php

arr array_udiff ( arr $array1 , arr $array2 [, 
                                               arr $arra3, ..., arr $arrayN ],
                                                               callable $value_compare_func )
 

where,

$array1 = The first ARRAY to compare from

$array2 = The second ARRAY to compare against

$array3 = The third ARRAY to compare against

. . . . . . . . . . . . . . .

$arrayN = The last ARRAY to compare against

$value_compare_func = The comparisson function

?>

$array1

The first ARRAY - to compare from.

$array2

The second ARRAY - to compare against.

$array3

The third ARRAY - to compare against.

$arrayN

The last ARRAY - to compare against.

$value_compare_func

The callback comparison function.

EXERCISE


<?php

function udcompare ($k1, $k2)
{
if ($k1 === $k2)
    {
    return 0;
    }
    elseif ($k1 > $k2)
    {
    return 1;
    }
    else
    {
    return -1;
    }
}

$arruV01a = [ "S" => 'string', "a" => 'array', 
                                            "n" => 'number', 
                                            "o" => 'object', "r" => 'resource' ];

$arruV01b = [ "s" => 'string', "A" => 'array', "r" => 'resource' ];

echo 'FIRST ARRAY:<br>';
print_r($arruV01a);

echo '<br><br>SECOND ARRAY:<br>';
print_r($arruV01b);

echo '<br><br><br>RESULTING ARRAY:<br>';

$arruV01ab = array_udiff ($arruV01a, 
                                         $arruV01b, 
                                        'udcompare');
print_r($arruV01ab);

?>

RESULT

FIRST ARRAY:
Array ( [S] => string [a] => array [n] => number [o] => object [r] => resource )

SECOND ARRAY:
Array ( [s] => string [A] => array [r] => resource )

RESULTING ARRAY:
Array ( [n] => number [o] => object )

Verify that all values of RESULTING ARRAY belong to FIRST ARRAY with the same keys as this one.

EXERCISE


<?php

function udcompare ($k1, $k2)
{
if ($k1 === $k2)
    {
    return 0;
    }
    elseif ($k1 > $k2)
    {
    return 1;
    }
    else
    {
    return -1;
    }
}

$arruV02a = [ "s" => 'string', "a" => 'array', 
                                            "n" => 'number', 
                                            "o" => 'object', "r" => 'resource' ];

$arruV02b = [ "S" => 'string', "a" => 'ARRAY', "r" => 'RESOURCE' ];

echo 'FIRST ARRAY:<br>';
print_r($arruV02a);

echo '<br><br>SECOND ARRAY:<br>';
print_r($arruV02b);

echo '<br><br><br>RESULTING ARRAY:<br>';

$arruV02ab = array_udiff ($arruV02a, 
                                          $arruV02b, 
                                         'udcompare');
print_r($arruV02ab);

?>

RESULT

FIRST ARRAY:
Array ( [s] => string [a] => array [n] => number [o] => object [r] => resource )

SECOND ARRAY:
Array ( [S] => string [a] => ARRAY [r] => RESOURCE )

RESULTING ARRAY:
Array ( [a] => array [n] => number [o] => object [r] => resource )

Verify that all values of RESULTING ARRAY belong to FIRST ARRAY with the same keys as this one.

This function is case-sensitive for both keys and values.