# array_udiff

(PHP 5, PHP 7, PHP 8)

array_udiffデータの比較にコールバック関数を用い、配列の差を計算する

### 説明

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

データの比較にコールバック関数を用い、配列の差を計算します。 この関数は array_diff() と異なり、 データの比較に内部関数を利用します。

### パラメータ

`array`

`arrays`

`value_compare_func`

callback(mixed `\$a`, mixed `\$b`): int

### 例

``` <?php// 比較する配列\$array1 = array(new stdclass, new stdclass,                new stdclass, new stdclass,               );\$array2 = array(                new stdclass, new stdclass,               );// オブジェクトにプロパティを設定します\$array1->width = 11; \$array1->height = 3;\$array1->width = 7;  \$array1->height = 1;\$array1->width = 2;  \$array1->height = 9;\$array1->width = 5;  \$array1->height = 7;\$array2->width = 7;  \$array2->height = 5;\$array2->width = 9;  \$array2->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'));?> ```

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

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

)
```

``` <?phpclass 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;        }    }}// 毎週の予約用のカレンダーを作ります\$myCalendar = new MyCalendar;// 今週の予約を入れます\$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.");// 空きが何日あるかを調べるため、\$booked の日数と \$free の日数を比べます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"; }?> ```

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

Tuesday
Thursday

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

Wednesday: Going on a snowboarding trip.
Friday: Fixing buggy code.
```

### 参考

• array_diff() - 配列の差を計算する
• array_diff_assoc() - 追加された添字の確認を含めて配列の差を計算する
• array_diff_uassoc() - ユーザーが指定したコールバック関数を利用し、 追加された添字の確認を含めて配列の差を計算する
• array_udiff_assoc() - データの比較にコールバック関数を用い、 追加された添字の確認を含めて配列の差を計算する
• array_udiff_uassoc() - データと添字の比較にコールバック関数を用い、 追加された添字の確認を含めて配列の差を計算する
• array_intersect() - 配列の共通項を計算する
• array_intersect_assoc() - 追加された添字の確認も含めて配列の共通項を確認する
• array_uintersect() - データの比較にコールバック関数を用い、配列の共通項を計算する
• array_uintersect_assoc() - データの比較にコールバック関数を用い、 追加された添字の確認も含めて配列の共通項を計算する
• array_uintersect_uassoc() - データと添字の比較に個別のコールバック関数を用い、 追加された添字の確認も含めて配列の共通項を計算する add a note

### User Contributed Notes 9 notes

40
Colin
15 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 to \$b, \$b, \$b, and \$b using the provided callback function.  If the callback returns zero for any of the comparisons then \$a will not be in the returned array from array_udiff().  It then compares \$a to \$b, \$b, \$b, and \$b.  Then, finally, \$a to \$b, \$b, \$b, and \$b.For example, compare_ids(\$a, \$b) === -5 while compare_ids(\$a, \$b) === 0.  Therefore, \$a 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) {  =>  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) {  =>  array(3) {    ["id"]=>    int(15)    ["name"]=>    string(5) "Nancy"    ["color"]=>    string(5) "black"  }  =>  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) {}?> ```
25
napcoder
5 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. ```
grantwparks at gmail dot com
13 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:<?phpfunction 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 (  => 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.) ```
13
adam dot jorgensen dot za at gmail dot com
13 years ago
``` It is not stated, by this function also diffs array1 to itself, removing any duplicate values... ```
10
b4301775 at klzlk dot com
10 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 (      => Array         (              => Bob              => 42         )      => Array         (              => Frank              => 39         ) ) 1 Hope this helps someone ```
Jorge Morales (morales2k)
2 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->width = 11; \$array1->height = 3;    \$array1->width = 7;  \$array1->height = 1;    \$array1->width = 2;  \$array1->height = 9;    \$array1->width = 5;  \$array1->height = 7;    \$array2->width = 7;  \$array2->height = 5;    \$array2->width = 9;  \$array2->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    (         => stdClass Object            (                [width] => 11                [height] => 3            )             => 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! ```
dmhouse at gmail dot com
16 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. ```
-1
jared
12 years ago
``` Note that php does the string conversion *before* sending the values to the callback function. ```
-2
aidan at php dot net
17 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 ``` 