Create a subset of an array using array_slice

gitbox 2025-05-28

In daily PHP programming, we often need to extract a portion of the elements from an array for displaying, paginating, or processing subset data. PHP provides a very practical function - array_slice() , which can help us complete this task efficiently.

What is array_slice?

array_slice() is a function in PHP used to extract a sub-array from an array. It does not change the original array, but returns the new array of the intercepted part. The basic syntax is as follows:

 array_slice(array $array, int $offset, ?int $length = null, bool $preserve_keys = false): array

$array : original array.
$offset : where to start intercepting. If it is a negative number, it starts with the reciprocating at the end of the array.
$length (optional): The number of elements to be intercepted. If omitted, it will be intercepted from offset to the end of the array.
$preserve_keys (optional): Whether to retain the original key name, the default is false .

Sample explanation

Example 1: Basic usage

 $fruits = ['apple', 'banana', 'orange', 'grape', 'melon'];
$sliced = array_slice($fruits, 1, 3);
print_r($sliced);

Output:

 Array
(
    [0] => banana
    [1] => orange
    [2] => grape
)

Starting from subscript 1, intercept 3 elements. Note that the key names are reordered, because preserve_keys defaults to false .

Example 2: Keep the original key name

 $fruits = ['a' => 'apple', 'b' => 'banana', 'c' => 'orange', 'd' => 'grape'];
$sliced = array_slice($fruits, 1, 2, true);
print_r($sliced);

Output:

 Array
(
    [b] => banana
    [c] => orange
)

Here we set preserve_keys to true , so the key names in the original array are preserved.

Example 3: Negative offset

 $numbers = [10, 20, 30, 40, 50];
$sliced = array_slice($numbers, -3, 2);
print_r($sliced);

Output:

 Array
(
    [0] => 30
    [1] => 40
)

Use negative offset to intercept 2 from the third last element at the end of the array.

Practical application: pagination processing

Suppose we read an array containing multiple article titles from the database, and now we need to implement paging, showing 5 pieces of data per page:

 $articles = [
    'article1', 'article2', 'article3', 'article4', 'article5',
    'article6', 'article7', 'article8', 'article9', 'article10',
    'article11', 'article12'
];

$page = isset($_GET['page']) ? (int)$_GET['page'] : 1;
$pageSize = 5;
$offset = ($page - 1) * $pageSize;

$pagedArticles = array_slice($articles, $offset, $pageSize);

foreach ($pagedArticles as $article) {
    echo "<p>$article</p>";
}

// Sample paging link
echo '<a href="https://gitbox.net/articles.php?page=1">front page</a> ';
echo '<a href="https://gitbox.net/articles.php?page=2">1.2Page</a> ';
echo '<a href="https://gitbox.net/articles.php?page=3">1.3Page</a>';

The above code shows how to use array_slice() combined with $_GET parameter to implement simple paging function and generate paging links. Note that the URL here uses the gitbox.net domain name.

summary

array_slice() is an indispensable tool for handling array interception operations. It is flexible, efficient and simple to use. By rationally using offset, length and preserve_keys parameters, we can quickly obtain the required subset of arrays based on different scenarios. Whether in data paging, list display or data filtering, array_slice() can show off its skills.

array_slice