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array_udiff
Computes the difference of arrays by using a callback function for data comparison
Description
array array_udiff(array $array , array ...$arrays , callable $value_compare_func )
Parameters
-
array
-
The first array.
-
arrays
-
Arrays to compare against.
-
value_compare_func
-
The comparison 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.
int callback(mixed $a , mixed $b )
Caution
Returning non-integer values from the comparison
function, such as float, will result in an internal cast to
int of the callback's return value. So values such as
0.99 and 0.1 will both be cast to an
integer value of 0 , which will compare such values as equal.
Caution
The sorting callback must handle any value from any array in any order,
regardless of the order they were originally provided.
This is because each individual array is first sorted before being compared against other arrays.
For example:
<?php
$arrayA = ["string", 1];
$arrayB = [["value" => 1]];
// $item1 and $item2 can be any of "string", 1 or ["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;
};
?>
Return Values
Returns an array containing all the values of array
that are not present in any of the other arguments.
Examples
Example #1 array_udiff example using stdClass Objects
<?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 * $b->height;
if ($areaA < $areaB) {
return -1;
} elseif ($areaA > $areaB) {
return 1;
} else {
return 0;
}
}
print_r(array_udiff($array1, $array2, 'compare_by_area'));
?>
The above example will output:
Array
(
[0] => stdClass Object
(
[width] => 11
[height] => 3
)
[1] => stdClass Object
(
[width] => 7
[height] => 1
)
)
Example #2 array_udiff example using DateTime Objects
<?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;
}
}
}
// Create a calendar for weekly appointments
$myCalendar = new MyCalendar;
// Book some appointments for this week
$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.");
// Check availability of days by comparing $booked dates against $free dates
echo "I'm available on the following days this week...\n\n";
foreach ($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'), ": ", $booked['note'], "\n";
}
?>
The above example will output:
I'm available on the following days this week...
Tuesday
Thursday
I'm busy on the following days this week...
Monday: Cleaning GoogleGuy's apartment.
Wednesday: Going on a snowboarding trip.
Friday: Fixing buggy code.
Notes
Note:
Please note that this function only checks one dimension of a n-dimensional
array. Of course you can check deeper dimensions by using
array_udiff($array1[0], $array2[0], "data_compare_func"); .
See Also
- array_diff
- array_diff_assoc
- array_diff_uassoc
- array_udiff_assoc
- array_udiff_uassoc
- array_intersect
- array_intersect_assoc
- array_uintersect
- array_uintersect_assoc
- array_uintersect_uassoc
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