PHP array key value inversion: a solution to improve performance

In PHP, inverting array key values ​​can improve performance. The following scheme can be used: array_flip() function: Creates a new array, the original array keys become new array values, and the original array values ​​become new array keys. foreach loop: manually invert the array and modify the value. array_map() function and closure: Flexibly invert the array and return an array of key-value pairs.

PHP array key value inversion: a solution to improve performance

Preface

Key-value inversion of arrays becomes critical when dealing with large data sets. It can significantly improve the performance of find and retrieval operations. In this article, we will explore different options for inverting array key values ​​in PHP and show how you can use them to optimize your application.

Option 1: array_flip() function

array_flip() function is the simplest way to invert the key values ​​of an array. It creates a new array where the keys of the original array become the values ​​of the new array and the values ​​of the original array become the keys of the new array.

$originalArray = ['name' => 'John', 'age' => 30];
$invertedArray = array_flip($originalArray);

// $invertedArray 输出：
// ['John' => 'name', '30' => 'age']

Option 2: Use a foreach loop

If you need more control or need to modify values, you can use a foreach loop to manually invert the array.

$originalArray = ['name' => 'John', 'age' => 30];
$invertedArray = [];

foreach ($originalArray as $key => $value) {
    $invertedArray[$value] = $key;
}

// $invertedArray 输出：
// ['John' => 'name', '30' => 'age']

Option 3: Use array_map() and Closure

array_map() Functions and closures (Closure) provide another kind of flexibility The method of inverting the key values ​​of an array.

$originalArray = ['name' => 'John', 'age' => 30];

$invertedArray = array_map(function ($value, $key) {
    return [$value, $key];
}, $originalArray);

// $invertedArray 输出：
// [['John', 'name'], ['30', 'age']]

Practical case

In the following practical case, we use the array_flip() function to optimize a function that finds user names in the database:

function findUserByName($name) {
    // 从数据库中获取所有用户
    $users = [
        ['id' => 1, 'name' => 'John Doe'],
        ['id' => 2, 'name' => 'Jane Smith'],
    ];

    // 倒置数组，以用户名为键
    $invertedUsers = array_flip($users);

    // 检查倒置数组中是否存在给定用户名
    if (!isset($invertedUsers[$name])) {
        return null;
    }

    // 返回与给定用户名关联的用户 ID
    return $invertedUsers[$name];
}

Inverted arrays can significantly improve application performance by speeding up lookup operations by many orders of magnitude.

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