在这里,我们创建了一个包含所有数组组合的数组,因此我们稍后可以获取这些数组的交集。
阵列组合
首先,我们需要创建所有可能的数组组合。这是:
c数组 1 * c数组 2 * ... * c数组 n
"c" 仅表示count()
数组的
因此,在您的具体示例中,它将是:
c数组 1 * c数组 2 => 2 * 2 => 4 种组合
现在我们需要获取所有这些组合并将它们放入一个数组中。为此,我们从一个空$combinations
数组开始。然后我们遍历数组中的所有组合并将下一个数组合并到其中,直到我们获得所需的组合长度,在这种情况下是我们拥有的数组的数量。
举个例子:
Array with the elements (Empty array is '[]'):
[
[[1, 3, 4], [1, 4]], //array 1
[[5, 4, 3, 2], [5, 3]], //array 2
]
1* combination array 2* new array //↓new combinations
↓ ↓ //↓for the next iteration
│
array NAN*:
Combinations:
- [] │ -> []
│
array 1: ┌──────────────────────────────────┘
│
Combinations: v
- [] + [1, 3, 4] │ -> [[1, 3, 4]]
- [] + [1, 4] │ -> [[1, 4]]
│
array 2: ┌──────────────────────────────────┘
│
Combinations: v
- [[1, 3, 4]] + [5, 4, 3, 2] │ -> [[1, 3, 4], [5, 4, 3, 2]]
- [[1, 3, 4]] + [5, 3] │ -> [[1, 3, 4], [5, 3]]
- [[1, 4]] + [5, 4, 3, 2] │ -> [[1, 4], [5, 4, 3, 2]]
- [[1, 4]] + [5, 3] │ -> [[1, 4], [5, 3]]
//↑ All combinations here
* NAN:不是数字
因此,正如您在上面的示例中看到的那样,我们现在拥有所有组合,其长度等于我们拥有的所有数组的长度(4 个组合,长度为 2 个元素)。
如上例所示,获取组合的代码是:
//for循环确保我们得到每个组合的所需长度
//(我们拥有的数组数量。这里是2)
for ($count = 0, $length = count($data); $count < $length; $count++) {
$tmp = [];
foreach ($combinations as $v1) { //1* 组合数组
foreach ($data[$count] as $v2) //2* 新数组
$tmp[] = array_merge($v1, [$v2]); //创建新的组合
}
$组合 = $tmp; //为下一次迭代分配新的组合
}
在您的具体示例中生成此数组:
Array
(
[0] => Array //Combination 1
(
[0] => Array
(
[0] => 1
[1] => 3
[2] => 4
)
[1] => Array
(
[0] => 5
[1] => 4
[2] => 3
[3] => 2
)
)
[1] => Array //Combination 2
(
[0] => Array
(
[0] => 1
[1] => 3
[2] => 4
)
[1] => Array
(
[0] => 5
[1] => 3
)
)
[2] => Array //Combination 3
(
[0] => Array
(
[0] => 1
[1] => 4
)
[1] => Array
(
[0] => 5
[1] => 4
[2] => 3
[3] => 2
)
)
[3] => Array //Combination 4
(
[0] => Array
(
[0] => 1
[1] => 4
)
[1] => Array
(
[0] => 5
[1] => 3
)
)
)
数组交集
现在我们有了所有组合,我们可以通过组合数组array_map()
并获取array_intersect()
每个组合的。而且由于我们不知道有多少数组需要交集,所以我们只使用call_user_func_array()
,例如
$intersections = array_map(function($v){
//intersection of each combination, which we created
return call_user_func_array("array_intersect", $v);
}, $combinations);
完整代码:
<?php
$array1 = [[1, 3, 4], [1, 4]];
$array2 = [[5, 4, 3, 2], [5, 3]];
function getIntersections($data = []) {
$combinations = [[]];
for ($count = 0, $length = count($data); $count < $length; $count++) {
$tmp = [];
foreach ($combinations as $v1) {
foreach ($data[$count] as $v2)
$tmp[] = array_merge($v1, [$v2]);
}
$combinations = $tmp;
}
$intersections = array_map(function($v){
return call_user_func_array("array_intersect", $v);
}, $combinations);
return $intersections;
}
$intersections = getIntersections([$array1, $array2]);
print_r($intersections);
?>
输出:
Array
(
[0] => Array //Intersection of: [1, 3, 4] && [5, 4, 3, 2]
(
[1] => 3
[2] => 4
)
[1] => Array //Intersection of: [1, 3, 4] && [5, 3]
(
[1] => 3
)
[2] => Array //Intersection of: [1, 4] && [5, 4, 3, 2]
(
[1] => 4
)
[3] => Array //Intersection of: [1, 4] && [5, 3]
(
)
)