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.

1. 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
?>

2. 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] ]`

3. 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>";
}
?>

4. 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>";
}
?>

5. 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>";
}
?>

6. 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)`

7. 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);
?>

8. 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);
?>

9. Removing Duplicate Values from an Array

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

10. 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