Comprehensive Guide to PHP Arrays with Examples

Introduction

Arrays are an essential part of PHP, allowing you to store and manage collections of data efficiently. This guide will walk you through the different types of arrays in PHP, how to create and manipulate them, and common functions to use with arrays.

Types of Arrays

Indexed Arrays

Indexed arrays use numeric keys to store and access data. The keys are automatically assigned starting from 0.

Creating an Indexed Array

$cars = array("Toyota", "BMW", "Mercedes");

You can also use the shorthand syntax:

$cars = ["Toyota", "BMW", "Mercedes"];

Accessing Elements

echo $cars[0]; // Outputs: Toyota

Associative Arrays

Associative arrays use named keys to store and access data.

Creating an Associative Array

$age = array("Peter" => 35, "Ben" => 37, "Joe" => 43);

Alternatively, using the shorthand syntax:

$age = ["Peter" => 35, "Ben" => 37, "Joe" => 43];

Accessing Elements

echo $age["Peter"]; // Outputs: 35

Multidimensional Arrays

Multidimensional arrays contain one or more arrays. These are used for more complex data structures.

Creating a Multidimensional Array

$cars = array(
    array("Volvo", 22, 18),
    array("BMW", 15, 13),
    array("Saab", 5, 2),
    array("Land Rover", 17, 15)
);

Accessing Elements

echo $cars[0][0]; // Outputs: Volvo
echo $cars[1][2]; // Outputs: 13

Array Functions

PHP provides a variety of functions to manipulate arrays. Here are some common ones:

count()

The count() function returns the number of elements in an array.

$cars = ["Toyota", "BMW", "Mercedes"];
echo count($cars); // Outputs: 3

array_merge()

The array_merge() function merges one or more arrays into one.

$array1 = ["color" => "red", 2, 4];
$array2 = ["a", "b", "color" => "green", "shape" => "trapezoid", 4];
$result = array_merge($array1, $array2);

print_r($result);

Outputs:

Array
(
    [color] => green
    [0] => 2
    [1] => 4
    [2] => a
    [3] => b
    [shape] => trapezoid
    [4] => 4
)

array_push()

The array_push() function adds one or more elements to the end of an array.

$stack = ["orange", "banana"];
array_push($stack, "apple", "raspberry");
print_r($stack);

Outputs:

Array
(
    [0] => orange
    [1] => banana
    [2] => apple
    [3] => raspberry
)

array_pop()

The array_pop() function removes the last element from an array and returns that element.

$stack = ["orange", "banana", "apple", "raspberry"];
$fruit = array_pop($stack);
print_r($stack);

Outputs:

Array
(
    [0] => orange
    [1] => banana
    [2] => apple
)

array_keys()

The array_keys() function returns all the keys of an array.

$array = ["color" => "red", "shape" => "trapezoid", "size" => "medium"];
$keys = array_keys($array);
print_r($keys);

Outputs:

Array
(
    [0] => color
    [1] => shape
    [2] => size
)

in_array()

The in_array() function checks if a value exists in an array.

$people = ["Peter", "Joe", "Glenn", "Cleveland"];
if (in_array("Glenn", $people)) {
    echo "Glenn is in the array";
}

array_search()

The array_search() function searches an array for a given value and returns the key if successful.

$people = ["Peter", "Joe", "Glenn", "Cleveland"];
$key = array_search("Joe", $people);
echo $key; // Outputs: 1

Conclusion

Arrays are a fundamental part of PHP programming, offering flexibility and efficiency for handling collections of data. This guide has covered the basics of creating and manipulating indexed, associative, and multidimensional arrays, as well as using some of the most common array functions. With this knowledge, you can effectively manage data in your PHP applications.