I want to stress that in the user function, you do need to return either a 1 or a -1 properly; you cannot simply return 0 if the results are equal and 1 if they are not.
The following code is incorrect:
<?php
function myfunction($v1,$v2)
{
if ($v1===$v2)
{
return 0;
}
return 1;
}
$a1=array(1, 2, 4);
$a2=array(1, 3, 4);
print_r(array_uintersect($a1,$a2,"myfunction"));
?>
This code is correct:
<?php
function myfunction($v1,$v2)
{
if ($v1===$v2)
{
return 0;
}
if ($v1 > $v2) return 1;
return -1;
}
$a1=array(1, 2, 4);
$a2=array(1, 3, 4);
print_r(array_uintersect($a1,$a2,"myfunction"));
?>
array_uintersect
(PHP 5, PHP 7)
array_uintersect — Computes the intersection of arrays, compares data by a callback function
설명
array array_uintersect
( array
$array1
, array $array2
[, array $...
], callable $value_compare_func
)Computes the intersection of arrays, compares data by a callback function.
인수
-
array1 -
The first array.
-
array2 -
The second array.
-
value_compare_func -
이 비교 함수는 첫번째 인수가 두번째 인수보다 작거나, 같거나, 클 경우에 각각 0보다 작거나, 같거나, 큰 정수를 반환해야 합니다.
반환값
Returns an array containing all the values of array1
that are present in all the arguments.
예제
Example #1 array_uintersect() example
<?php
$array1 = array("a" => "green", "b" => "brown", "c" => "blue", "red");
$array2 = array("a" => "GREEN", "B" => "brown", "yellow", "red");
print_r(array_uintersect($array1, $array2, "strcasecmp"));
?>
위 예제의 출력:
Array
(
[a] => green
[b] => brown
[0] => red
)
참고
- array_intersect() - 배열의 교집합을 계산
- array_intersect_assoc() - 인덱스 검사과 함께 배열의 교집합을 계산
- array_uintersect_assoc() - Computes the intersection of arrays with additional index check, compares data by a callback function
- array_uintersect_uassoc() - Computes the intersection of arrays with additional index check, compares data and indexes by separate callback functions
add a note
User Contributed Notes 4 notes
Nate at RuggFamily dot com ¶
17 years ago
rob dot c dot ruiz at gmail dot com ¶
6 years ago
When trying to do a case insensitive comparison between arrays of words, the strcasecmp function works very nicely with this one like so:
$arr1 = array('blue', 'green', 'red');
$arr2 = array('BLUE', 'Purple', 'Red');
$loose_matches = array_uintersect($arr1, $arr2, 'strcasecmp');
print_r($loose_matches) // array('blue', 'red');
Hayley Watson ¶
6 years ago
As for the other "compare function" callbacks, the return value from the callback function doesn't need to be -1, 0, or 1.
cmp($a,$b) just needs to be <0, =0, or >0 depending on whether $a<$b, $a=$b, or $a>$b.
Ryan C ¶
2 years ago
If you're rolling your own comparison function, keep in mind that the spaceship operator (i.e. <=>) can be your best friend. It's been around since PHP7. https://www.php.net/manual/en/language.operators.comparison.php
So, for instance, instead of a clunky function like:
<?php
function myFunction($v1, $v2) {
if ($v1 === $v2) {
return 0;
}
if ($v1 > $v2) return 1;
return -1;
}
?>
You can simplify it to:
<?php
function myFunction($v1, $v2) {
return $v1 <=> $v2;
}
?>
