PHP array_splice Function

last modified March 13, 2025

The PHP array_splice function removes/replaces array elements and optionally inserts new elements. It's a powerful array modification tool.

Basic Definition

array_splice removes elements from an array and replaces them with optional new elements. It modifies the original array and returns the removed elements.

Syntax: array_splice(array &$array, int $offset, ?int $length = null, mixed $replacement = []): array. The function works with numeric keys and reindexes the array.

Basic Removal Example

This shows how to remove elements from an array starting at a position.

basic_removal.php

<?php

$colors = ['red', 'green', 'blue', 'yellow'];
$removed = array_splice($colors, 1, 2);

print_r($colors);    
print_r($removed);

This removes 2 elements starting from index 1. The original array is modified, and removed elements are returned. Note the reindexing.

Inserting Elements

Demonstrates how to insert new elements without removing any existing ones.

insert_elements.php

<?php

$fruits = ['apple', 'banana', 'cherry'];
array_splice($fruits, 1, 0, ['orange', 'grape']);

print_r($fruits);

By setting length to 0, we insert new elements at position 1 without removing any. The array grows to accommodate the new elements.

Replacing Elements

Shows how to replace existing elements with new ones in a single operation.

replacement.php

<?php

$numbers = [1, 2, 3, 4, 5];
$removed = array_splice($numbers, 1, 3, ['two', 'three', 'four']);

print_r($numbers);  
print_r($removed);

This replaces 3 elements starting at index 1 with new string values. The function returns the original elements that were replaced.

Negative Offset

Demonstrates using negative offsets to count from the end of the array.

negative_offset.php

<?php

$letters = ['a', 'b', 'c', 'd', 'e'];
array_splice($letters, -2, 1);

print_r($letters);

A negative offset counts from the end (-1 is last element). Here we remove one element starting from the second-to-last position ('d' is removed).

Complete Replacement

Shows how to replace the entire array contents with new elements.

complete_replacement.php

<?php

$original = ['old1', 'old2', 'old3'];
$removed = array_splice($original, 0, count($original), ['new1', 'new2']);

print_r($original);  
print_r($removed);

By specifying the full array length, we replace all elements. The original array now contains only the new elements we provided.

Best Practices

Backup Arrays: Copy arrays before splicing if original needed.
Return Values: Remember it returns removed elements.
Reindexing: Be aware it reindexes numeric keys.
Performance: Minimize large array modifications.

Source

PHP array_splice Documentation

This tutorial covered the PHP array_splice function with practical examples showing its usage for array modification scenarios.

Author

My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.

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