Fast calculation algorithm for array intersection in PHP

A fast algorithm for calculating array intersection in PHP is to use the array_intersect() function, which returns all intersection elements. The algorithm steps are as follows: Create arrays to be compared. Use the array_intersect() function to calculate intersection. Gets the result, which is a new array containing all intersection elements. Intersection elements are further processed as needed.

PHP Fast calculation algorithm for array intersection

In PHP, array intersection is to find out the difference between two or more arrays The set of all elements that exist. Computing array intersection is a common operation, especially when comparing or merging data.

Fast calculation algorithm

A fast algorithm for calculating the intersection of arrays is to use the array_intersect() function. This function accepts two or more arrays as arguments and returns a new array containing all intersection elements. Here are the steps of the algorithm:

<?php
// 创建两个数组
$arr1 = [1, 2, 3, 4, 5];
$arr2 = [2, 4, 6, 8];

// 使用 array_intersect() 函数计算交集
$intersection = array_intersect($arr1, $arr2);

// 打印交集
print_r($intersection);
?>

Output:

Array
(
    [0] => 2
    [1] => 4
)

Practical Case

Suppose we have an online store and need to find out what has been purchased customers for two specific products. You can use the array_intersect() function to calculate the intersection of buyers of these two products:

<?php
// 获取购买了第一种产品的客户 ID
$customerIds1 = [1, 3, 5, 7, 9];

// 获取购买了第二种产品的客户 ID
$customerIds2 = [2, 4, 6, 8, 10];

// 计算交集以找出购买了两种产品的客户
$commonCustomerIds = array_intersect($customerIds1, $customerIds2);

// 进一步处理共同客户的 ID
?>

The above is the detailed content of Fast calculation algorithm for array intersection in PHP. For more information, please follow other related articles on the PHP Chinese website!