PHP array_slice(): Get Part of an Array

array_slice($array, $offset, $length) returns a new array with $length elements starting at position $offset. The original array is not changed. Leave out $length to take everything up to the end.

<?php
$letters = ["a", "b", "c", "d", "e", "f"];

print_r(array_slice($letters, 0, 3)); // first three
print_r(array_slice($letters, 2));    // from position 2 to the end
print_r($letters);                    // unchanged

The offset is a position (0 is the first element), not a key. That matters for associative arrays and for arrays whose keys are not 0, 1, 2.

Get the last N elements with a negative offset

A negative offset counts from the end: -1 is the last element, -3 starts three from the end. A negative length stops that many elements before the end.

<?php
$log = ["boot", "login", "upload", "resize", "logout"];

print_r(array_slice($log, -2));     // last two
print_r(array_slice($log, 1, -1));  // drop the first and the last
print_r(array_slice($log, -3, 2));  // two, starting three from the end

Asking for more elements than exist is fine: array_slice($log, 0, 100) returns all five.

Keep the original keys with preserve_keys

Integer keys are renumbered from 0 unless you pass true as the fourth argument. String keys are always kept.

<?php
$ranked = [10 => "gold", 20 => "silver", 30 => "bronze", 40 => "fourth"];

print_r(array_slice($ranked, 1, 2));
print_r(array_slice($ranked, 1, 2, true));

$prices = ["tea" => 3, "coffee" => 4, "juice" => 5, "water" => 1];
print_r(array_slice($prices, 1, 2)); // string keys kept anyway

Use true when the keys mean something, such as database ids, and you will look elements up by them later.

Paginate an array with array_slice

Showing page $page of a list with $perPage items per page is one slice: the offset is ($page - 1) * $perPage. This example prints an HTML list with page links. Run it and click a page number: the same script runs again with $_GET['page'] set from the link.

<?php
$items = [];
for ($i = 1; $i <= 23; $i++) {
    $items[] = "Item $i";
}

$perPage = 5;
$pages = (int) ceil(count($items) / $perPage);
$page = max(1, min($pages, (int) ($_GET['page'] ?? 1)));

$visible = array_slice($items, ($page - 1) * $perPage, $perPage);

echo "<p>Page $page of $pages</p>\n<ul>\n";
foreach ($visible as $item) {
    echo "  <li>$item</li>\n";
}
echo "</ul>\n<p>";
for ($p = 1; $p <= $pages; $p++) {
    echo $p === $page ? " <strong>$p</strong>" : " <a href=\"?page=$p\">$p</a>";
}
echo "</p>\n";

The max(1, min($pages, ...)) line keeps a hand-typed ?page=99 or ?page=-1 inside the valid range. With a database you would ask for only one page with LIMIT and OFFSET instead of loading every row, but for a list already in memory, array_slice is the whole job.

array_slice vs array_splice

The names differ by one letter and they do opposite things to the original. array_slice copies a part out. array_splice cuts the part out of the array you pass, renumbers it, and returns the removed elements. It can also insert replacements where the cut was.

<?php
$a = ["mon", "tue", "wed", "thu", "fri"];
$copy = array_slice($a, 1, 2);
echo "slice returned: " . implode(", ", $copy) . "\n";
echo "original now:   " . implode(", ", $a) . "\n\n";

$b = ["mon", "tue", "wed", "thu", "fri"];
$cut = array_splice($b, 1, 2);
echo "splice returned: " . implode(", ", $cut) . "\n";
echo "original now:    " . implode(", ", $b) . "\n\n";

$c = ["mon", "tue", "wed", "thu", "fri"];
array_splice($c, 1, 2, ["TUE", "WED", "extra"]);
echo "replaced: " . implode(", ", $c) . "\n";

For more ways to delete elements, see removing elements from an array.

Split an array into chunks

When you need every page at once, for example to lay products out in rows of three, array_chunk does the repeated slicing for you.

<?php
$products = ["Lamp", "Desk", "Chair", "Shelf", "Rug", "Mirror", "Clock"];

foreach (array_chunk($products, 3) as $i => $row) {
    echo "Row " . ($i + 1) . ": " . implode(" | ", $row) . "\n";
}

Change the 3 to 2 or 4 and run it again. The last chunk holds whatever is left over.