How to find the intersection of three integer arrays in PHP

With the development of Internet technology, more and more websites now need to process and analyze large amounts of data. These data often require operations such as intersection and union before the required results can be obtained. Today we will discuss how to find the intersection of three integer arrays using PHP.

1. Problem Description

Given three integer arrays $a$, $b$, $c$, please write a PHP function to calculate their intersection.

For example, given the following three arrays:

$a = [1, 2, 3, 4, 5];
$b = [2, 3, 4, 5, 6];
$c = [3, 4, 5, 7, 8];

Output:

[3, 4, 5]

Because $3$, $4$, $5$ exist in three arrays.

2. Problem-solving ideas

To find the intersection of three integer arrays, you can use the array_intersect() function in PHP. This function is used to calculate the intersection of multiple arrays. Its syntax is as follows:

array_intersect(array1, array2, ..., arrayX)

where, array1, array2,..., arrayX are multiple arrays to be compared, and the function will return their intersection. If there is no intersection, an empty array is returned.

Therefore, we can pass the given three arrays as parameters to the array_intersect() function, and then output the return result. The specific implementation code is as follows:

<?php
function intersect($a, $b, $c) {
    return array_intersect($a, $b, $c);
}

$a = [1, 2, 3, 4, 5];
$b = [2, 3, 4, 5, 6];
$c = [3, 4, 5, 7, 8];

$result = intersect($a, $b, $c);
print_r($result);
?>

The above code defines an intersect() function, which accepts three parameters $a$, $b$, $c$, representing three parameters respectively. Array of integers. Inside the function, we pass these three arrays as parameters to the array_intersect() function and return the result directly to the function caller.

Finally, we define three arrays $a$, $b$, $c$ in the main program and pass them as parameters to the intersect() function. The result returned by the function is stored in the $result variable, and we use the print_r() function to print it out.

3. Summary

This article discusses how to use PHP to calculate the intersection of three integer arrays. By using the array_intersect() function, we can easily solve for the intersection of multiple arrays, avoiding manually writing complex algorithms and reducing the possibility of errors. In actual web development, we can apply this method to various data processing and analysis scenarios to improve the efficiency and effectiveness of the program.

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