PHP Array

In PHP, an array is a data structure that can store multiple values under a single variable name. PHP arrays are versatile and can hold a mix of data types, such as integers, strings, and even other arrays. There are three main types of arrays in PHP:

Indexed Arrays: Arrays with numeric indexes.
Associative Arrays: Arrays with named keys.
Multidimensional Arrays: Arrays containing other arrays.

1. Indexed Arrays

Indexed arrays use numeric indexes, starting from 0. Here's how you can create and use them:
Creating an Indexed Array

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

Accessing Elements

php
echo $fruits[0]; // Outputs: Apple
echo $fruits[1]; // Outputs: Banana

Adding Elements

php
$fruits[] = "Date"; // Adds "Date" to the end of the array

2. Associative Arrays

Associative arrays use named keys that you assign to them. This allows you to access values based on their keys.
Creating an Associative Array

php
$person = array(
    "first_name" => "John",
    "last_name" => "Doe",
    "age" => 30
);

Accessing Elements

php
echo $person["first_name"]; // Outputs: John
echo $person["age"];        // Outputs: 30

Adding Elements

php
$person["email"] = "john.doe@example.com";

3. Multidimensional Arrays

Multidimensional arrays are arrays of arrays. They can be useful for storing complex data.
Creating a Multidimensional Array

php
$students = array(
    array("John", "Doe", 20),
    array("Jane", "Smith", 22),
    array("Sam", "Brown", 19)
);

Accessing Elements

php
echo $students[0][0]; // Outputs: John
echo $students[1][2]; // Outputs: 22

Adding Elements

php
$students[1][] = "A"; // Adds a new element to the second student's array

Useful Array Functions

PHP provides a variety of functions to manipulate arrays:

    array_push($array, $value) - Adds one or more elements to the end of an array.
    array_pop($array) - Removes the last element from an array.
    array_shift($array) - Removes the first element from an array.
    array_unshift($array, $value) - Adds one or more elements to the beginning of an array.
    array_merge($array1, $array2) - Merges two or more arrays.
    array_keys($array) - Returns all the keys of an array.
    array_values($array) - Returns all the values of an array.
    in_array($value, $array) - Checks if a value exists in an array.

Here's an example using some of these functions:

php
$numbers = array(1, 2, 3);
// Add elements
array_push($numbers, 4, 5);
// Remove the last element
array_pop($numbers);
// Merge arrays
$more_numbers = array(6, 7, 8);
$all_numbers = array_merge($numbers, $more_numbers);
// Check if a value exists
if (in_array(4, $all_numbers)) {
    echo "4 is in the array";
}

Summary

Arrays in PHP are powerful and flexible, allowing you to store and manipulate multiple values efficiently. Understanding how to use and manipulate arrays is crucial for effective PHP programming.