Quickly calculate array intersection and union using bitwise operations in PHP

In PHP, array intersections and unions can be efficiently calculated through bitwise operators: Intersection: Using the bitwise AND operator (&), co-existing elements are intersections. Union: Using the bitwise OR operator (|), the union contains all elements.

Use bitwise operations in PHP to quickly calculate the intersection and union of arrays

The bitwise operators provide the implementation of arrays in PHP Efficient methods for intersection and union. These operators operate on numbers bit by bit, allowing us to compare array values ​​on a binary bit level.

Intersection

The intersection contains elements that appear in both arrays. We can use the bitwise AND operator & to calculate the intersection:

<?php

$array1 = [1, 2, 3, 4, 5];
$array2 = [3, 4, 5, 6, 7];

$intersection = array_intersect_bitwise($array1, $array2);

var_dump($intersection); // 输出: [3, 4, 5]
?>

Union

The union contains all the elements in both arrays . We can use the bitwise OR operator | to calculate the union:

<?php

$array1 = [1, 2, 3, 4, 5];
$array2 = [3, 4, 5, 6, 7];

$union = array_union_bitwise($array1, $array2);

var_dump($union); // 输出: [1, 2, 3, 4, 5, 6, 7]
?>

Practical case: Calculate the pages visited by the user

Suppose you There is an array containing the pages visited by the user:

<?php

$userPages = [
    'Home',
    'About',
    'Contact'
];

$adminPages = [
    'Dashboard',
    'Users',
    'Settings',
    'About'
];
?>

You can use bitwise operations to quickly find out the pages visited by both the user and the administrator:

<?php

$intersection = array_intersect_bitwise($userPages, $adminPages);

var_dump($intersection); // 输出: ['About']
?>

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