array_udiff

(PHP 5, PHP 7, PHP 8)

array_udiff — Computa a diferença de arrays usando uma função de callback para comparação dos dados

Descrição

array_udiff ( array $array1 , array $array2 , array $ ... = ? , callback $data_compare_func ) : array

Computa a diferença de arrays usando uma função de callback para comparação dos dados. Esta é contrária a array_diff() que usa uma função interna para comparar os dados.

Parâmetros

array1

O primeiro array.

array2

O segundo array.

data_compare_func

A função de callback de comparação.

A função de callback fornecida pelo usuário é usada para comparação. Ela deve retornar um inteiro menor que, igual a, ou maior que zero se o primeiro argumento é considerado respectivamente, menor que, igual a, ou maior que o segundo.

Valor Retornado

Retorna um array contendo todos os valores de array1 que não estão presentes em qualquer dos outros argumentos.

Exemplos

Exemplo #1 Exemplo de array_udiff()


<?php
class cr {
    private $priv_member;
    function cr($val)
    {
        $this->priv_member = $val;
    }

    static function comp_func_cr($a, $b)
    {
        if ($a->priv_member === $b->priv_member) return 0;
        return ($a->priv_member > $b->priv_member)? 1:-1;
    }
}
$a = array("0.1" => new cr(9), "0.5" => new cr(12), 0 => new cr(23), 1=> new cr(4), 2 => new cr(-15),);
$b = array("0.2" => new cr(9), "0.5" => new cr(22), 0 => new cr(3), 1=> new cr(4), 2 => new cr(-15),);

$result = array_udiff($a, $b, array("cr", "comp_func_cr"));
print_r($result);
?>

O exemplo acima irá imprimir:

Array
(
    [0.5] => cr Object
        (
            [priv_member:private] => 12
        )

    [0] => cr Object
        (
            [priv_member:private] => 23
        )

)

Notas

Nota: Por favor note que esta função somente checa uma dimensão de um array n-dimensional. É claro que você pode checar dimensões mais profundas usando array_udiff($array1[0], $array2[0], "data_compare_func");.

Veja Também

array_diff() - Computa as diferenças entre arrays
array_diff_assoc() - Computa a diferença entre arrays com checagem adicional de índice
array_diff_uassoc() - Computa a diferença entre arrays com checagem adicional de índice que feita por uma função de callback fornecida pelo usuário
array_udiff_assoc() - Computa a diferença entre arrays com checagem adicional de índice, compara dados por uma função de callback
array_udiff_uassoc() - Computa a diferença entre arrays com checagem adicional de índice, compara dados e índices por uma função de callback
array_intersect() - Calcula a interseção entre arrays
array_intersect_assoc() - Computa a interseção de arrays com uma adicional verificação de índice
array_uintersect() - Computa a interseção de array, comparando dados com uma função callback
array_uintersect_assoc() - Computa a interseção de arrays com checagem adicional de índice, compara os dados utilizando uma função de callback
array_uintersect_uassoc() - Computa a interseção de arrays com checagem adicional de índice, compara os dados e os índices utilizando funções de callback separadas

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User Contributed Notes 9 notes

down

Colin ¶

17 years ago


I think the example given here using classes is convoluting things too much to demonstrate what this function does.

array_udiff() will walk through array_values($a) and array_values($b) and compare each value by using the passed in callback function.

To put it another way, array_udiff() compares $a[0] to $b[0], $b[1], $b[2], and $b[3] using the provided callback function.  If the callback returns zero for any of the comparisons then $a[0] will not be in the returned array from array_udiff().  It then compares $a[1] to $b[0], $b[1], $b[2], and $b[3].  Then, finally, $a[2] to $b[0], $b[1], $b[2], and $b[3].

For example, compare_ids($a[0], $b[0]) === -5 while compare_ids($a[1], $b[1]) === 0.  Therefore, $a[1] is not returned from array_udiff() since it is present in $b.

<?
$a = array(
        array(
                'id' => 10,
                'name' => 'John',
                'color' => 'red',
        ),
        array(
                'id' => 20,
                'name' => 'Elise',
                'color' => 'blue',
        ),
        array(
                'id' => 30,
                'name' => 'Mark',
                'color' => 'red',
        ),
);

$b = array(
        array(
                'id' => 15,
                'name' => 'Nancy',
                'color' => 'black',
        ),
        array(
                'id' => 20,
                'name' => 'Elise',
                'color' => 'blue',
        ),
        array(
                'id' => 30,
                'name' => 'Mark',
                'color' => 'red',
        ),
        array(
                'id' => 40,
                'name' => 'John',
                'color' => 'orange',
        ),
);

function compare_ids($a, $b)
{
    return ($a['id'] - $b['id']);
}
function compare_names($a, $b)
{
    return strcmp($a['name'], $b['name']);
}

$ret = array_udiff($a, $b, 'compare_ids');
var_dump($ret);

$ret = array_udiff($b, $a, 'compare_ids');
var_dump($ret);

$ret = array_udiff($a, $b, 'compare_names');
var_dump($ret);
?>

Which returns the following.

In the first return we see that $b has no entry in it with an id of 10.
<?
array(1) {
  [0]=>
  array(3) {
    ["id"]=>
    int(10)
    ["name"]=>
    string(4) "John"
    ["color"]=>
    string(3) "red"
  }
}
?>

In the second return we see that $a has no entry in it with an id of 15 or 40.
<?
array(2) {
  [0]=>
  array(3) {
    ["id"]=>
    int(15)
    ["name"]=>
    string(5) "Nancy"
    ["color"]=>
    string(5) "black"
  }
  [3]=>
  array(3) {
    ["id"]=>
    int(40)
    ["name"]=>
    string(4) "John"
    ["color"]=>
    string(6) "orange"
  }
}
?>

In third return we see that all names in $a are in $b (even though the entry in $b whose name is 'John' is different, the anonymous function is only comparing names).
<?
array(0) {
}
?>

down

napcoder ¶

7 years ago


Note that the compare function is used also internally, to order the arrays and choose which element compare against in the next round.

If your compare function is not really comparing (ie. returns 0 if elements are equals, 1 otherwise), you will receive an unexpected result.

down

grantwparks at gmail dot com ¶

16 years ago


Re: "convoluted"

I think the point being made is that array_udiff() can be used not only for comparisons between homogenous arrays, as in your example (and definitely the most common need), but it can be used to compare heterogeneous arrays, too.

Consider:

<?php
function compr_1($a, $b) {
    $aVal = is_array($a) ? $a['last_name'] : $a;
    $bVal = is_array($b) ? $b['last_name'] : $b;
    return strcasecmp($aVal, $bVal);
}

$aEmployees = array(
    array('last_name'  => 'Smith',
            'first_name' => 'Joe',
            'phone'      => '555-1000'),
    array('last_name'  => 'Doe',
            'first_name' => 'John',
            'phone'      => '555-2000'),
    array('last_name'  => 'Flagg',
            'first_name' => 'Randall',
            'phone'      => '666-1000')
    );

$aNames = array('Doe', 'Smith', 'Johnson');
    
$result = array_udiff($aEmployees, $aNames, "compr_1");

print_r($result);
?>

Allowing me to get the "employee" that's not in the name list:

Array ( [2] => Array ( [last_name] => Flagg [first_name] => Randall [phone] => 666-1000 ) )

Something interesting to note, is that the two arguments to the compare function don't correspond to array1 and array2.  That's why there has to be logic in it to handle that either of the arguments might be pointing to the more complex employee array.  (Found this out the hard way.)

down

adam dot jorgensen dot za at gmail dot com ¶

15 years ago


It is not stated, by this function also diffs array1 to itself, removing any duplicate values...

down

b4301775 at klzlk dot com ¶

12 years ago


Quick example for using array_udiff to do a multi-dimensional diff



Returns values of $arr1 that are not in $arr2



<?php

$arr1 = array( array('Bob', 42), array('Phil', 37), array('Frank', 39) );

        

$arr2 = array( array('Phil', 37), array('Mark', 45) );

        

$arr3 = array_udiff($arr1, $arr2, create_function(

    '$a,$b',

    'return strcmp( implode("", $a), implode("", $b) ); ')

    );

        

print_r($arr3);

?>



Output:



Array

(

    [0] => Array

        (

            [0] => Bob

            [1] => 42

        )

 

    [2] => Array

        (

            [0] => Frank

            [1] => 39

        )

 

)

1



Hope this helps someone

down

Jorge Morales (morales2k) ¶

5 years ago


I find it that this is an ideal place to apply the spaceship operator, but it was not used in the examples. 

Here is Example#1 using the spaceship operator in the comparison function. 

    <?php
    // Arrays to compare
    $array1 = array(new stdclass, new stdclass,
                    new stdclass, new stdclass,
                   );

    $array2 = array(
                    new stdclass, new stdclass,
                   );

    // Set some properties for each object
    $array1[0]->width = 11; $array1[0]->height = 3;
    $array1[1]->width = 7;  $array1[1]->height = 1;
    $array1[2]->width = 2;  $array1[2]->height = 9;
    $array1[3]->width = 5;  $array1[3]->height = 7;

    $array2[0]->width = 7;  $array2[0]->height = 5;
    $array2[1]->width = 9;  $array2[1]->height = 2;

    function compare_by_area($a, $b) {
        $areaA = $a->width * $a->height;
        $areaB = $b->width * $b->height;
    
        return $areaA <=> $areaB;
    }

    print_r(array_udiff($array1, $array2, 'compare_by_area'));
    ?>

The output is:
    Array
    (
        [0] => stdClass Object
            (
                [width] => 11
                [height] => 3
            )
    
        [1] => stdClass Object
            (
                [width] => 7
                [height] => 1
            )
    
    )

I find it is pretty awesome you can substitute all of these lines:
    if ($areaA < $areaB) {
        return -1;
    } elseif ($areaA > $areaB) {
        return 1;
    } else {
        return 0;
    }

with just:

    return $areaA <=> $areaB;

Neat!

down

dmhouse at gmail dot com ¶

19 years ago


Very easy way of achieving a case-insensitive version of array_diff (or indeed array_diff_assoc, array_intersect or any of these types of functions which have a similar function that takes a callback function as one of their parameters):

array_udiff($array1, $array2, 'strcasecmp');

This works because strcasecmp() compares two strings case-insensitively, as compared to the array_diff() which compares two strings by using the == operator, which is case-sensitive.

down

-1

jared ¶

14 years ago


Note that php does the string conversion *before* sending the values to the callback function.

down

-2

aidan at php dot net ¶

19 years ago


This functionality is now implemented in the PEAR package PHP_Compat.

More information about using this function without upgrading your version of PHP can be found on the below link:

http://pear.php.net/package/PHP_Compat

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