PHP Arrays (Step-by-Step Guide with Examples)

Arrays are a fundamental part of PHP that allow you to store multiple values in a single variable. They are versatile, efficient, and widely used in PHP programming.

What Is an Array in PHP?

An array is a data structure that holds multiple values under a single variable. Each value in an array is assigned an index (key), making it easy to access and manipulate data.

Example: Creating an Array

<?php
$fruits = ["Apple", "Banana", "Orange"];
echo $fruits[0]; // Output: Apple
?>

Types of Arrays in PHP

PHP supports three types of arrays:

Array Type	Description	Example
Indexed Array	Uses numeric indexes (0, 1, 2, …)	`["Apple", "Banana", "Cherry"]`
Associative Array	Uses named keys instead of numeric indexes	`["name" => "John", "age" => 25]`
Multidimensional Array	Contains arrays inside another array	`[ ["Apple", 10], ["Banana", 20] ]`

Indexed Arrays

Creating an Indexed Array

<?php
$colors = ["Red", "Blue", "Green"];
echo $colors[1]; // Output: Blue
?>

Adding Elements to an Array

<?php
$colors[] = "Yellow"; // Adds "Yellow" to the array
?>

Looping Through an Indexed Array

<?php
$colors = ["Red", "Blue", "Green"];
foreach ($colors as $color) {
    echo $color . "<br>";
}
?>

Associative Arrays

Associative arrays use named keys instead of numeric indexes.

Creating an Associative Array

<?php
$person = ["name" => "John", "age" => 30, "city" => "New York"];
echo $person["name"]; // Output: John
?>

Adding New Key-Value Pairs

<?php
$person["job"] = "Developer";
?>

Looping Through an Associative Array

<?php
$person = ["name" => "John", "age" => 30, "city" => "New York"];
foreach ($person as $key => $value) {
    echo "$key: $value <br>";
}
?>

Multidimensional Arrays

A multidimensional array is an array of arrays.

Example: 2D Array

<?php
$students = [
    ["Alice", 20, "A"],
    ["Bob", 22, "B"],
    ["Charlie", 21, "A"]
];
echo $students[0][0]; // Output: Alice
?>

Looping Through a Multidimensional Array

<?php
foreach ($students as $student) {
    echo "Name: " . $student[0] . ", Age: " . $student[1] . ", Grade: " . $student[2] . "<br>";
}
?>

PHP Array Functions

PHP provides built-in functions to manipulate arrays easily.

Common Array Functions

Function	Description	Example
`count()`	Returns number of elements	`count($arr)`
`array_push()`	Adds element to the end	`array_push($arr, "PHP")`
`array_pop()`	Removes last element	`array_pop($arr)`
`array_merge()`	Merges two arrays	`array_merge($arr1, $arr2)`
`in_array()`	Checks if a value exists	`in_array("PHP", $arr)`
`array_keys()`	Gets all keys from an array	`array_keys($arr)`
`array_values()`	Gets all values from an array	`array_values($arr)`
`sort()`	Sorts an array in ascending order	`sort($arr)`
`rsort()`	Sorts an array in descending order	`rsort($arr)`
`asort()`	Sorts associative array by values	`asort($arr)`
`ksort()`	Sorts associative array by keys	`ksort($arr)`

Sorting Arrays in PHP

Sorting Indexed Arrays

<?php
$numbers = [4, 2, 8, 1];
sort($numbers);
print_r($numbers); // Output: [1, 2, 4, 8]
?>

Sorting Associative Arrays by Value

<?php
$ages = ["John" => 30, "Alice" => 25, "Bob" => 27];
asort($ages);
print_r($ages);
?>

Sorting Associative Arrays by Key

<?php
ksort($ages);
print_r($ages);
?>

Converting Arrays to Strings & Vice Versa

Convert Array to String (Implode)

<?php
$colors = ["Red", "Blue", "Green"];
echo implode(", ", $colors); // Output: Red, Blue, Green
?>

Convert String to Array (Explode)

<?php
$text = "PHP, JavaScript, Python";
$languages = explode(", ", $text);
print_r($languages);
?>

Removing Duplicate Values from an Array

<?php
$numbers = [1, 2, 2, 3, 4, 4, 5];
$unique_numbers = array_unique($numbers);
print_r($unique_numbers);
?>

Filtering Arrays in PHP

You can use array_filter() to remove elements based on conditions.

Example: Filtering Even Numbers

<?php
$numbers = [1, 2, 3, 4, 5, 6];
$evenNumbers = array_filter($numbers, function($num) {
    return $num % 2 == 0;
});
print_r($evenNumbers); // Output: [2, 4, 6]
?>

PHP arrays are powerful and flexible, allowing you to store and manipulate data efficiently. Whether you use indexed, associative, or multidimensional arrays, mastering arrays will enhance your PHP skills.

Next Steps:
Practice using arrays in real projects
Experiment with array functions
**Explore advanced array operations