How does PHP handle the summation problem of the intersection of two-dimensional arrays?

In PHP programming, we often encounter the situation of processing arrays, among which the summation of the intersection of two-dimensional arrays is a common problem. This article will introduce how to use PHP language to handle the summation problem of the intersection of two-dimensional arrays.

1. What is a two-dimensional array?

Two-dimensional array means that each element in an array is itself an array, in which each element represents an independent data item.

For example, the two-dimensional array below contains three sub-arrays, and each sub-array contains three data items.

$arr ​​= array(

array(1,2,3),
array(4,5,6),
array(7,8,9)

)

2. What is array intersection?

Array intersection refers to a new array composed of elements that exist in both arrays.

For example, the following two arrays:

$arr1 = array(1,3,5,7,9);
$arr2 = array(2,4,6, 8,9);

Their intersection is:

array(9)

3. Method of summing the intersection of two-dimensional arrays

two-dimensional Array intersection summation means that given two two-dimensional arrays, perform an intersection operation on each of their sub-arrays, and then add the intersection values ​​of all sub-arrays to get a sum.

For example, the following two two-dimensional arrays:

$array1 = array(
array(1,2,3,4),
array(2,3,4 ,5),
array(3,4,5,6)
);

$array2 = array(
array(3,4,5,6),
array(5,6,7,8),
array(7,8,9,10)
);

The intersection summation can be implemented with the following code:

$sum = 0;
foreach ($array1 as $subarray1) { // Traverse the subarray in array 1
foreach ($array2 as $subarray2) { // Traverse the subarray in array 2

$intersect = array_intersect($subarray1, $subarray2); // 对子数组进行交集操作
if (!empty($intersect)) { // 如果交集不为空
  $sum += array_sum($intersect); // 将交集中的值相加
}

}
}
echo $sum; // Output result: 33

4. Example description

The above code will traverse the items in array 1 each subarray, then loop through each subarray in array 2, do an intersection operation on them, and add the values ​​in the intersection to the $sum variable.

In the specific implementation, the array_intersect() function is used to perform the intersection operation. If the intersection is not empty, the array_sum() function is used to add the values ​​in the intersection.

It should be noted that when using the array_intersect() function, if the intersection of two sub-arrays is empty, an empty array will be returned. Therefore, when judging whether the intersection is empty, you need to use the !empty() function Make judgments.

5. Summary

This article introduces the basic concepts and implementation methods of two-dimensional array intersection summation in PHP. I hope it will be useful to PHP programming beginners and developers who need to deal with array intersections. help. If you have any questions or suggestions about this article, please leave a message.

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