PHP Indexed Array – Store and Access Ordered Data in PHP

A complete guide to creating, accessing, and working with indexed arrays in PHP.

Introduction – What Is an Indexed Array?

An indexed array in PHP is a type of array where elements are assigned numeric keys starting from 0 by default. It’s perfect for storing ordered lists of items such as colors, numbers, or product names.

In this guide, you’ll learn:

• How to create and access indexed arrays
• Looping techniques for indexed arrays
• Common operations like sorting and counting
• Real-world usage and best practices

Creating Indexed Arrays

Using Square Bracket Syntax (Preferred)

$colors = ["red", "green", "blue"];

Using array() Function (Legacy)

$colors = array("red", "green", "blue");

Accessing Indexed Array Elements

$colors = ["red", "green", "blue"];

echo $colors[0]; // red
echo $colors[1]; // green

Array indexes start at 0 and increase by one for each element.

Looping Through Indexed Arrays

Using foreach Loop

$fruits = ["apple", "banana", "cherry"];

foreach ($fruits as $fruit) {
    echo $fruit . "<br>";
}

Using for Loop

$fruits = ["apple", "banana", "cherry"];

for ($i = 0; $i < count($fruits); $i++) {
    echo $fruits[$i] . "<br>";
}

Use foreach for cleaner syntax unless you need the index.

Add, Update, and Remove Elements

Add New Item

$colors[] = "yellow"; // adds to the end

Update Existing Item

$colors[1] = "lime"; // replaces "green" with "lime"

Remove an Item

unset($colors[2]); // removes "blue"

Useful Indexed Array Functions

Indexed vs Associative Arrays

Best Practices

• Use [] syntax for simplicity
• Loop with foreach unless you need the index
• Don’t mix associative keys in indexed arrays
• Use count() to avoid hardcoding loop limits

Summary – Recap & Next Steps

PHP indexed arrays are the simplest way to handle ordered collections of data. They’re widely used for lists, dropdowns, menu items, and more.

Key Takeaways:

• Indexed arrays use numeric keys starting from 0
• Use [] or array() to define them
• Easily loop through using foreach or for
• PHP provides many helpful array functions for manipulation

Real-World Use Cases:
Navigation menus, ordered product lists, color swatches, and dropdown fields.

Frequently Asked Questions (FAQs)

What is the default index of a PHP array?
If not specified, it starts from 0 and increments by 1.

Can I skip index numbers in an indexed array?
Yes, but doing so turns it into a non-continuous indexed array.

How to check if a value exists in an indexed array?
Use in_array("value", $array);

Can I mix keys in an indexed array?
Technically yes, but it’s not recommended for clarity and consistency.