Compare different ways to remove duplicate elements from arrays in PHP

There are many ways to remove duplicate elements from an array in PHP, including: using the array_unique() function (which returns a new array containing only unique values), using the array_flip() and array_keys() functions (by exchanging key values ​​and getting key to remove duplicates), use set() data structure (guaranteed to contain only unique elements, can be converted to an array). Practical case: Use the array_unique() function to remove duplicate user names and obtain unique user names in a given array.

Different methods to remove duplicate elements from arrays in PHP

In PHP programming, it is often necessary to process arrays, one of which A common operation is to remove duplicate elements. This article will introduce several common PHP methods to achieve this purpose.

Use the array_unique() function

array_unique() The function is the simplest way to remove duplicate elements from an array. This function returns a new array containing only the unique values ​​in the original array.

$array = [1, 2, 3, 4, 5, 1, 2, 3];
$uniqueArray = array_unique($array);

print_r($uniqueArray); // 输出 [1, 2, 3, 4, 5]

Use the array_flip() function and the array_keys() function

array_flip() The function can interchange keys and values ​​in an array, and the array_keys() function can return an array of keys in an array.

$array = [1, 2, 3, 4, 5, 1, 2, 3];
$uniqueKeys = array_keys(array_flip($array));

print_r($uniqueKeys); // 输出 [1, 2, 3, 4, 5]

Use set() Data structure

##set() The data structure is an unordered set that can Guaranteed to contain only unique elements. We can convert an array to set() and then convert it back to an array.

$array = [1, 2, 3, 4, 5, 1, 2, 3];
$set = new Set($array);
$uniqueArray = $set->toArray();

print_r($uniqueArray); // 输出 [1, 2, 3, 4, 5]

Practical case: filtering duplicate user names

The following is a practical case demonstrating how to use the

array_unique() function to remove duplicate user names:

Suppose we have an array containing usernames and need to remove duplicate usernames from it.

$usernames = ['john', 'doe', 'mary', 'jane', 'john', 'mary'];

We can use the

array_unique() function to remove duplicate usernames:

$uniqueUsernames = array_unique($usernames);

Now, the

$uniqueUsernames array contains only unique usernames .

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