What built-in functions are available for PHP array deduplication?

PHP provides a variety of built-in functions for array deduplication, including: array_unique(): retain unique elements and return a new array. array_intersect_key(): Cross-compare keys, retaining only the values ​​corresponding to keys that exist in the first array. array_unique() array_values(): Remove duplicates first, then re-index, retaining only unique elements.

PHP Array Deduplication Built-in Function Guide

In PHP, deduplicating arrays is a common task. PHP provides a variety of built-in functions to help you accomplish this task easily and efficiently.

1. array_unique() function

array_unique() The function deduplicates an array by retaining the unique elements in the array. It returns a new array containing the deduplicated elements.

<?php
$array = ['foo', 'bar', 'baz', 'foo', 'bar'];
$uniqueArray = array_unique($array);

Output:

Array
(
    [0] => foo
    [1] => bar
    [2] => baz
)

2. array_intersect_key() function

array_intersect_key() Function combines the keys of multiple arrays Cross comparison, retaining only the values ​​corresponding to keys that exist in the first array. This effectively deduplicates the array.

<?php
$array1 = ['foo' => 1, 'bar' => 2, 'baz' => 3];
$array2 = ['foo' => 4, 'baz' => 5];
$uniqueArray = array_intersect_key($array1, $array2);

Output:

Array
(
    [foo] => 1
    [baz] => 3
)

3. array_unique() array_values() function

array_unique() function and array_values() functions can also be used in combination to deduplicate arrays. array_unique() The function first removes duplicate elements, and then the array_values() function re-indexes the array, retaining only unique elements.

<?php
$array = ['foo', 'bar', 'baz', 'foo', 'bar'];
$uniqueArray = array_values(array_unique($array));

Output:

Array
(
    [0] => foo
    [1] => bar
    [2] => baz
)

Practical case

The following is a practical case demonstrating how to use array_unique()# in a Web application ## Functions to deduplicate user input:

<?php
// 获取用户输入
$userInput = $_POST['user_input'];

// 将用户输入转换为数组
$array = explode(",", $userInput);

// 对数组进行去重
$uniqueArray = array_unique($array);

// 保存去重后的数组
// ...

Using these built-in functions, you can easily and efficiently deduplicate PHP arrays, simplifying your code and improving performance.

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