array_udiff

(PHP 5, PHP 7, PHP 8)

array_udiff Ermittelt den Unterschied zwischen Arrays mittels einer Callbackfunktion für den Datenvergleich

Beschreibung

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

Ermittelt den Unterschied zwischen Arrays mittels einer Callbackfunktion für den Datenvergleich. Dies ist anders als bei array_diff(), das eine interne Funktion zum Vergleichen der Daten verwendet.

Parameter-Liste

array

Das erste Array.

arrays

Arrays zum Vergleichen.

value_compare_func

Die Vergleichsfunktion muss einen Integer kleiner als, gleich oder größer als Null zurückgeben, wenn das erste Argument respektive kleiner, gleich oder größer als das zweite ist.

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

Wenn die Vergleichsfunktion nicht-ganzzahlige Werte zurückgibt, z. B. vom Typ float, wird der Rückgabewert des Callbacks intern in den Typ int umgewandelt. Werte wie 0.99 und 0.1 werden also beide in einen Integer-Wert von 0 umgewandelt, wodurch diese Werte als gleichwertig eingestuft werden.

Achtung

Das Sortier-Callback muss alle Werte aus allen Arrays in beliebiger Reihenfolge verarbeiten, unabhängig von der Reihenfolge, in der sie ursprünglich bereitgestellt wurden. Das liegt daran, dass jedes einzelne Array zuerst sortiert wird, bevor es mit anderen Arrays verglichen wird. Zum Beispiel:

<?php
$arrayA
= ["string", 1];
$arrayB = [["value" => 1]];
// $item1 und $item2 können "string", 1 oder ["value" => 1] sein.
$compareFunc = static function ($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;
};
?>

Rückgabewerte

Gibt ein Array zurück, das alle Werte von array enthält, die nicht in einem der anderen Argumente vorhanden sind.

Beispiele

Beispiel #1 array_udiff() Beispiel mit stdClass Objekten

<?php
// Die zu vergleichenden Arrays
$array1 = array(new stdClass, new stdClass,
new
stdClass, new stdClass,
);

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

// Setze einige Eigenschaften für jedes Objekt
$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'));
?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

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

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

)

Beispiel #2 array_udiff() Beispiel mit DateTime Objekten

<?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;
}
}
}

// Erzeuge einen Kalender für wöchentliche Termine
$myCalendar = new MyCalendar;

// Buche einige Termine für diese Woche
$myCalendar->bookAppointment(new DateTime('Monday this week'), "GoogleGuys Wohnung reinigen.");
$myCalendar->bookAppointment(new DateTime('Wednesday this week'), "Snowboard fahren gehen.");
$myCalendar->bookAppointment(new DateTime('Friday this week'), "Fehlerhaften Code beheben.");

// Prüfe die Verfügbarkeit von Tagen durch Vergleichen von $booked Daten mit $free Daten
echo "Ich bin an den folgenden Tagen dieser Woche verfügbar...\n\n";
foreach (
$myCalendar->checkAvailability() as $free) {
echo
$free->format('l'), "\n";
}
echo
"\n\n";
echo
"Ich bin an den folgenden Tagen dieser Woche beschäftigt...\n\n";
foreach (
$myCalendar->booked as $booked) {
echo
$booked['date']->format('l'), ": ", $booked['note'], "\n";
}
?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

Ich bin an den folgenden Tagen dieser Woche verfügbar...

Tuesday
Thursday


Ich bin an den folgenden Tagen dieser Woche beschäftigt...

Monday: GoogleGuys Wohnung reinigen.
Wednesday: Snowboard fahren gehen.
Friday: Fehlerhaften Code beheben.

Anmerkungen

Hinweis: Bitte beachten Sie, dass diese Funktion nur eine Dimension eines n-dimensionalen Arrays überprüft. Natürlich können Sie tiefere Dimensionen prüfen, indem Sie array_udiff($array1[0], $array2[0], "data_compare_func"); verwenden.

Siehe auch

  • array_diff() - Ermittelt die Unterschiede zwischen Arrays
  • array_diff_assoc() - Berechnet den Unterschied zwischen Arrays mit zusätzlicher Indexprüfung
  • array_diff_uassoc() - Berechnet den Unterschied von Arrays mit zusätzlicher Indexprüfung, welche durch eine benutzerdefinierte Callback-Funktion vorgenommen wird
  • array_udiff_assoc() - Ermittelt den Unterschied zwischen Arrays mit zusätzlicher Indexprüfung, vergleicht mittels einer Callbackfunktion
  • array_udiff_uassoc() - Ermittelt den Unterschied zwischen Arrays mit zusätzlicher Indexprüfung, vergleicht Daten und Indizes mittels einer Callbackfunktion
  • array_intersect() - Ermittelt die Schnittmenge von Arrays
  • array_intersect_assoc() - Ermittelt die Schnittmenge von Arrays mit zusätzlicher Indexprüfung
  • array_uintersect() - Ermittelt die Schnittmenge von Arrays, vergleicht Daten mittels einer Callbackfunktion
  • array_uintersect_assoc() - Ermittelt die Schnittmenge von Arrays mit zusätzlicher Indexprüfung, vergleicht Daten mittels einer Callbackfunktion
  • array_uintersect_uassoc() - Ermittelt die Schnittmenge von Arrays mit zusätzlicher Indexprüfung, vergleicht Daten und Schlüssel mittels separaten Callbackfunktionen

add a note add a note

User Contributed Notes 9 notes

up
35
Colin
18 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
12
napcoder
8 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
3
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
12
adam dot jorgensen dot za at gmail dot com
16 years ago
It is not stated, by this function also diffs array1 to itself, removing any duplicate values...
up
10
b4301775 at klzlk dot com
13 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
0
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
0
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
-1
jared
15 years ago
Note that php does the string conversion *before* sending the values to the callback function.
up
-2
aidan at php dot net
20 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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