Indexed Arrays

Introduction to Arrays

Arrays in PHP are used to store multiple values in a single variable. Instead of creating separate variables for each value, arrays allow you to organize related data together.

Arrays are useful when working with lists of names, numbers, products, records, and other grouped information in web applications.

Objectives

By the end of this training, you will be able to:

• Understand the concept of arrays
• Create and use arrays in PHP
• Access array elements
• Modify array values
• Use different types of arrays
• Loop through arrays
• Apply array functions in PHP

What is an Array

An array is a special variable that can hold more than one value at a time.

Example:

<?php
$colors = array("Red", "Blue", "Green");
?>

In this example, the variable $colors stores three different values.

Why Use Arrays

Arrays help developers:

• Store multiple values efficiently
• Organize data in a structured way
• Reduce repetitive variables
• Simplify data processing
• Manage dynamic web content

Types of Arrays in PHP

PHP supports three main types of arrays:

Indexed Arrays

Indexed arrays use numeric indexes.

Example:

<?php
$fruits = array("Apple", "Banana", "Mango");

echo $fruits[0];
?>

Output:

Apple

Associative Arrays

Associative arrays use named keys instead of numbers.

Example:

<?php
$student = array(
    "name" => "Ali",
    "age" => 20,
    "city" => "Lahore"
);

echo $student["name"];
?>

Output:

Ali

Multidimensional Arrays

Multidimensional arrays contain multiple arrays inside another array.

Example:

<?php
$students = array(
    array("Ali", 20),
    array("Ahmed", 22),
    array("Sara", 19)
);

echo $students[0][0];
?>

Output:

Ali

Accessing Array Elements

You can access array elements using indexes or keys.

Example:

<?php
$cars = array("Toyota", "Honda", "BMW");

echo $cars[1];
?>

Output:

Honda

Updating Array Values

You can modify existing array values easily.

Example:

<?php
$colors = array("Red", "Blue", "Green");

$colors[1] = "Black";

echo $colors[1];
?>

Output:

Black

Adding New Elements to Arrays

Example:

<?php
$animals = array("Cat", "Dog");

$animals[] = "Horse";

print_r($animals);
?>

Looping Through Arrays

Using For Loop

Example:

<?php
$numbers = array(10, 20, 30);

for($i = 0; $i < count($numbers); $i++) {
    echo $numbers[$i];
}
?>

Using Foreach Loop

Example:

<?php
$colors = array("Red", "Blue", "Green");

foreach($colors as $color) {
    echo $color;
}
?>

Common Array Functions

count()

Returns the total number of elements.

<?php
$items = array("Pen", "Book", "Bag");

echo count($items);
?>

sort()

Sorts an array in ascending order.

<?php
$numbers = array(40, 10, 30, 20);

sort($numbers);

print_r($numbers);
?>

array_push()

Adds elements to the end of an array.

<?php
$fruits = array("Apple", "Banana");

array_push($fruits, "Orange");

print_r($fruits);
?>

Real World Uses of Arrays

Arrays are commonly used in:

• Student management systems
• Shopping carts
• Product listings
• User data storage
• Website menus
• Reports and dashboards

Advantages of Arrays

• Easy data management
• Faster data processing
• Better code organization
• Reusable and scalable
• Useful for dynamic applications

Best Practices for Arrays

• Use meaningful variable names
• Choose the correct array type
• Keep arrays organized
• Avoid unnecessary nested arrays
• Use built-in PHP array functions for efficiency

Final Presentation

In your final presentation, explain:

• What arrays are in PHP
• Types of arrays
• How to create and access arrays
• Difference between indexed and associative arrays
• Array loops and functions
• Real-world applications of arrays