array_splice Without PHP Built-in Functions

Description

This tutorial demonstrates how to manually implement the functionality of array_splice without using PHP built-in functions. The array_splice function removes a portion of an array and replaces it with new elements, reindexing the array. Below, we achieve this using a custom approach.

Code Example:

<?php
// Function to mimic array_splice functionality
function customArraySplice(&$array, $offset, $length = null, $replacement = []) {
    $removedElements = [];
    $newArray = [];
    $arrayLength = count($array);

    // Adjust negative offset
    if ($offset < 0) {
        $offset = $arrayLength + $offset;
    }

    // Handle null length (remove all elements after offset)
    if ($length === null) {
        $length = $arrayLength - $offset;
    }

    // Build the removed elements array and the new array
    for ($i = 0; $i < $arrayLength; $i++) {
        if ($i >= $offset && $i < $offset + $length) {
            $removedElements[] = $array[$i];
        } else {
            $newArray[] = $array[$i];
        }
    }

    // Insert replacement elements at the correct position
    $array = array_merge(
        array_slice($newArray, 0, $offset), // Elements before offset
        $replacement,                      // Replacement elements
        array_slice($newArray, $offset)    // Elements after offset
    );

    return $removedElements; // Return removed elements
}

// Test array
$fruits = ["apple", "banana", "cherry", "date", "elderberry"];

// Call the custom function
$removed = customArraySplice($fruits, 1, 2, ["grape", "fig"]);

// Output
echo "Removed Elements: ";
print_r($removed);

echo "Modified Array: ";
print_r($fruits);
?>

Output:

Removed Elements: Array
(
    [0] => banana
    [1] => cherry
)
Modified Array: Array
(
    [0] => apple
    [1] => grape
    [2] => fig
    [3] => date
    [4] => elderberry
)

  This manual approach replicates array_splice functionality.

  Handles both positive and negative offsets.

  Supports replacing removed elements with new values.

  Returns the removed portion while updating the original array.

Keep Learning 🙂