PHP Remove Array Items

Just as items get added to an array, they often need to be taken back out -- removing a completed task from a to-do list, deleting a cancelled order, or trimming an array down to just the values that still matter. PHP offers several functions for removing items, each suited to a slightly different situation.

In this page:

Removing a Specific Item with unset()
Removing the Last Item with array_pop()
Removing the First Item with array_shift()
Removing Items That Match a Condition with array_filter()
Removing All Items and Emptying an Array

Syntax

php

unset($array[key]);         // remove one item
array_pop($array);          // remove the last
array_shift($array);        // remove the first

Removing a Specific Item with unset()

unset($arr["key"]) removes exactly one item by its key or index, deleting it from the array entirely -- but on an indexed array, this leaves a gap where that index used to be, since the remaining items are not automatically renumbered.

Note: If you need a clean, gap-free indexed array after removing an item, follow unset() with array_values() to renumber the remaining items.

Warning: unset() leaving a gap in numeric keys can break code elsewhere that assumes indexes are always sequential starting at 0.

Example: Removing a Specific Item with unset()

php

<?php
// Declare `$arr` as an array: `["a", "b", "c"]`
$arr = ["a", "b", "c"];
// Remove `$arr[1]`
unset($arr[1]);
// Print a human-readable dump of `$arr`
print_r($arr);
?>

Removing the Last Item with array_pop()

array_pop($arr) removes the last item from an array and returns that removed value, modifying the original array directly -- a common pattern for treating an array like a stack, where the most recently added item is the first one processed back out.

Note: array_pop() naturally keeps indexed arrays gap-free, since it always removes from the very end rather than the middle.

Warning: Calling array_pop() on an already-empty array returns null rather than raising an error, so check the array is non-empty first if that distinction matters.

Example: Removing the Last Item with array_pop()

php

<?php
// Declare `$stack` as an array: `["a", "b", "c"]`
$stack = ["a", "b", "c"];
// Declare `$last`, set to `array_pop($stack)`
$last = array_pop($stack);
// Print `$last . "\n"` to the output
echo $last . "\n";
// Print a human-readable dump of `$stack`
print_r($stack);
?>

Removing the First Item with array_shift()

array_shift($arr) removes and returns the first item of an array, then automatically re-indexes every remaining numeric key downward by one -- useful for processing a queue where items should be handled in the order they were added.

Note: array_shift() automatically fixes numeric indexing after removal, unlike unset(), which is one reason to prefer it specifically for removing the first item.

Warning: array_shift() is slower than array_pop() on large arrays, since every remaining element's index has to shift down by one.

Example: Removing the First Item with array_shift()

php

<?php
// Declare `$queue` as an array: `["a", "b", "c"]`
$queue = ["a", "b", "c"];
// Declare `$first`, set to `array_shift($queue)`
$first = array_shift($queue);
// Print `$first . "\n"` to the output
echo $first . "\n";
// Print a human-readable dump of `$queue`
print_r($queue);
?>

Removing Items That Match a Condition with array_filter()

array_filter($arr, $callback) returns a brand-new array containing only the items for which $callback returns true, effectively filtering out (removing) everything that does not pass -- unlike the other removal functions here, it does not modify the original array.

Note: Reassign the result of array_filter() back to a variable (often the same one) since it returns a new array rather than modifying the original in place.

Warning: array_filter() preserves the original keys of the items that remain, which can leave gaps in numeric indexing -- pair it with array_values() if a clean re-indexed result is needed.

Example: Removing Items That Match a Condition with array_filter()

php

<?php
// Declare `$numbers` as an array: `[1, 2, 3, 4, 5]`
$numbers = [1, 2, 3, 4, 5];
$odd = array_filter($numbers, function ($n) {
    // Return `$n % 2 !== 0` from this function
    return $n % 2 !== 0;
});
// Print a human-readable dump of `$odd`
print_r($odd);
?>

Removing All Items and Emptying an Array

Assigning an empty array literal, $arr = [], instantly clears out every item, resetting the variable to a fresh, empty array -- the simplest way to remove everything at once, such as clearing a cart after checkout completes.

Note: Clearing an array with $arr = [] is simpler and more common than looping and unset()-ing every individual item one at a time.

Warning: Reassigning $arr = [] creates a brand-new empty array; if other variables held a reference to the original array, they are not automatically cleared too.

Example: Removing All Items and Emptying an Array

php

<?php
// Declare `$cart` as an array: `["item1", "item2"]`
$cart = ["item1", "item2"];
// Declare `$cart` as an empty array
$cart = [];
// Print a human-readable dump of `$cart`
print_r($cart);
?>

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