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array_udiff

(PHP 5, PHP 7, PHP 8)

array_udiffCalcule la différence entre deux tableaux en utilisant une fonction rappel

Description

array_udiff(array $array, array ...$arrays, callable $value_compare_func): array

Calcule la différence entre deux tableaux en utilisant une fonction rappel. Cette fonctionne agit comme la fonction array_diff() qui utilise une fonction interne pour comparer les données.

Liste de paramètres

array

Le premier tableau.

arrays

Tableaux à comparer contre

value_compare_func

La fonction de comparaison.

La fonction de comparaison doit retourner un entier inférieur à, égal à, ou supérieur à 0 si le premier argument est considéré comme, respectivement, inférieur à, égal à, ou supérieur au second.

callback(mixed $a, mixed $b): int
Attention

Retourner des valeurs non-entières à partir de la fonction de comparaison, telles que float, entraînera une conversion interne de la valeur de retour du rappel en int. Ainsi, des valeurs telles que 0.99 et 0.1 seront toutes deux converties en une valeur entière de 0, ce qui comparera de telles valeurs comme égales.

Attention

La fonction de rappel de tri doit traiter n'importe quelle valeur de n'importe quel tableau dans n'importe quel ordre, quel que soit l'ordre dans lequel elles ont été initialement fournies. Cela s'explique par le fait que chaque tableau individuel est d'abord trié avant d'être comparé aux autres tableaux. Par exemple :

<?php
$arrayA
= ["chaîne", 1];
$arrayB = [["value" => 1]];
// $item1 et $item2 peuvent être l'une des valeurs suivantes : "chaîne", 1 ou ["value" => 1]
$compareFunc = static function ($item1, $item2) {
$value1 = is_string($item1) ? strlen($item1) : (is_array($item1) ? $item1["value"] : $item1);
$value2 = is_string($item2) ? strlen($item2) : (is_array($item2) ? $item2["value"] : $item2);
return
$value1 <=> $value2;
};
?>

Valeurs de retour

Retourne un tableau contenant toutes les valeurs du tableau array qui ne sont pas présentes dans aucun autre argument.

Exemples

Exemple #1 Exemple avec array_udiff() en utilisant les objets stdClass

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

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

// Définit quelques propriétés pour chaque objet
$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;

if (
$areaA < $areaB) {
return -
1;
} elseif (
$areaA > $areaB) {
return
1;
} else {
return
0;
}
}

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

L'exemple ci-dessus va afficher :

Array
(
    [0] => stdClass Object
        (
            [width] => 11
            [height] => 3
        )

    [1] => stdClass Object
        (
            [width] => 7
            [height] => 1
        )

)

Exemple #2 Exemple avec array_udiff() en utilisant des objets DateTime

<?php
class MyCalendar {
public
$free = array();
public
$booked = array();

public function
__construct($week = 'now') {
$start = new DateTime($week);
$start->modify('Monday this week midnight');
$end = clone $start;
$end->modify('Friday this week midnight');
$interval = new DateInterval('P1D');
foreach (new
DatePeriod($start, $interval, $end) as $freeTime) {
$this->free[] = $freeTime;
}
}

public function
bookAppointment(DateTime $date, $note) {
$this->booked[] = array('date' => $date->modify('midnight'), 'note' => $note);
}

public function
checkAvailability() {
return
array_udiff($this->free, $this->booked, array($this, 'customCompare'));
}

public function
customCompare($free, $booked) {
if (
is_array($free)) $a = $free['date'];
else
$a = $free;
if (
is_array($booked)) $b = $booked['date'];
else
$b = $booked;
if (
$a == $b) {
return
0;
} elseif (
$a > $b) {
return
1;
} else {
return -
1;
}
}
}

// Crée un calendrier pour les rendez-vous hébdomadaires
$myCalendar = new MyCalendar;

// Enregistre quelques rendez-vous pour cette semaine
$myCalendar->bookAppointment(new DateTime('Monday this week'), "Cleaning GoogleGuy's apartment.");
$myCalendar->bookAppointment(new DateTime('Wednesday this week'), "Going on a snowboarding trip.");
$myCalendar->bookAppointment(new DateTime('Friday this week'), "Fixing buggy code.");

// Vérifie la disponibilité en jours, en comparant les dates $booked avec les dates $free
echo "I'm available on the following days this week...\n\n";
foreach (
$myCalendar->checkAvailability() as $free) {
echo
$free->format('l'), "\n";
}
echo
"\n\n";
echo
"I'm busy on the following days this week...\n\n";
foreach (
$myCalendar->booked as $booked) {
echo
$booked['date']->format('l'), ": ", $booked['note'], "\n";
}
?>

L'exemple ci-dessus va afficher :

I'm available on the following days this week...

Tuesday
Thursday


I'm busy on the following days this week...

Monday: Cleaning GoogleGuy's apartment.
Wednesday: Going on a snowboarding trip.
Friday: Fixing buggy code.

Notes

Note: Notez que cette fonction ne vérifie qu'une seule dimension d'un tableau multidimensionnel. Vous pouvez, bien sûr, tester une dimension particulière en utilisant par exemple array_udiff($array1[0], $array2[0], "data_compare_func");.

Voir aussi

  • array_diff() - Calcule la différence entre des tableaux
  • array_diff_assoc() - Calcule la différence de deux tableaux, en prenant aussi en compte les clés
  • array_diff_uassoc() - Calcule la différence entre deux tableaux associatifs, à l'aide d'une fonction de rappel
  • array_udiff_assoc() - Calcule la différence entre des tableaux avec vérification des index, compare les données avec une fonction de rappel
  • array_udiff_uassoc() - Calcule la différence de deux tableaux associatifs, compare les données et les index avec une fonction de rappel
  • array_intersect() - Calcule l'intersection de tableaux
  • array_intersect_assoc() - Calcule l'intersection de deux tableaux avec des tests sur les index
  • array_uintersect() - Calcule l'intersection de deux tableaux, compare les données en utilisant une fonction de rappel
  • array_uintersect_assoc() - Calcule l'intersection de deux tableaux avec des tests sur l'index, compare les données en utilisant une fonction de rappel
  • array_uintersect_uassoc() - Calcule l'intersection de deux tableaux avec des tests sur l'index, compare les données et les index des deux tableaux en utilisant une fonction de rappel séparée

add a note

User Contributed Notes 9 notes

up
52
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) {
}
?>
up
32
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.
up
7
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.)
up
17
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...
up
15
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
up
3
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!
up
2
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.
up
-2
jared
14 years ago
Note that php does the string conversion *before* sending the values to the callback function.
up
-3
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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