PHP Arrays – Complete Tutorial with Examples

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In this chapter, we will learn everything about PHP Arrays, including:

• What arrays are
• Types of arrays in PHP
• Built-in array functions
• Best practices for handling arrays
• Real-world use cases of arrays in PHP

By the end of this tutorial, you will be able to create, manipulate, and optimize arrays in PHP like a pro.

You will Learn

1. Introduction to PHP Arrays
2. Why Use Arrays in PHP?
3. Types of Arrays in PHP
   • Indexed Arrays
   • Associative Arrays
   • Multidimensional Arrays
4. Creating Arrays in PHP
5. Accessing Array Elements
6. Modifying Arrays in PHP
7. Looping Through Arrays
8. Array Functions in PHP
9. Sorting Arrays
10. Searching in Arrays
11. Array Length and Count
12. Adding & Removing Elements
13. Merging Arrays
14. Splitting & Slicing Arrays
15. PHP Arrays and Strings
16. Arrays with Forms and User Input
17. Arrays in Database Queries
18. Arrays in JSON and APIs
19. Multidimensional Array Deep Dive
20. Nested Arrays and Loops
21. Performance Tips with Arrays
22. Best Practices for Using Arrays
23. Common Mistakes in Arrays
24. Real-World Examples of PHP Arrays

1. Introduction to PHP Arrays

An array in PHP is a special variable that can hold multiple values at once. Instead of creating separate variables for each value, we can store them in an array.

For example:

$fruit1 = "Apple";
$fruit2 = "Banana";
$fruit3 = "Orange";

Instead of writing three variables, we can use an array:

$fruits = ["Apple", "Banana", "Orange"];

2. Why Use Arrays in PHP?

Arrays are essential because they:

• Store multiple values in one variable
• Reduce code duplication
• Allow looping through values
• Work with functions and databases
• Are used in real-world PHP applications like:
  • Shopping carts
  • User management systems
  • CMS (WordPress, Drupal)
  • API data processing

3. Types of Arrays in PHP

PHP supports 3 types of arrays:

1. Indexed Arrays – Use numeric indexes
2. Associative Arrays – Use named keys
3. Multidimensional Arrays – Arrays inside arrays

3.1 Indexed Arrays

Example:

$colors = ["Red", "Green", "Blue"];
echo $colors[0]; // Red

3.2 Associative Arrays

Example:

$person = [
    "name" => "Alice",
    "age" => 25,
    "city" => "Delhi"
];
echo $person["name"]; // Alice

3.3 Multidimensional Arrays

Example:

$students = [
    ["John", 20, "A"],
    ["Alice", 22, "B"],
    ["Bob", 19, "C"]
];
echo $students[0][0]; // John

4. Creating Arrays in PHP

$numbers = array(1, 2, 3, 4, 5);
$fruits = ["Mango", "Pineapple", "Apple"];

5. Accessing Array Elements

$fruits = ["Apple", "Banana", "Orange"];
echo $fruits[1]; // Banana

6. Modifying Arrays in PHP

$fruits[1] = "Grapes";
echo $fruits[1]; // Grapes

7. Looping Through Arrays

$fruits = ["Apple", "Banana", "Orange"];
foreach ($fruits as $fruit) {
    echo $fruit . "<br>";
}

8. Array Functions in PHP

PHP provides 100+ built-in array functions.

Examples:

$numbers = [1, 2, 3, 4, 5];

echo count($numbers); // 5
echo in_array(3, $numbers); // true
print_r(array_reverse($numbers));

9. Sorting Arrays

$fruits = ["Banana", "Apple", "Orange"];
sort($fruits);
print_r($fruits); // Apple, Banana, Orange

10. Searching in Arrays

$numbers = [10, 20, 30, 40];
echo array_search(30, $numbers); // 2

11. Array Length

$fruits = ["Apple", "Banana", "Orange"];
echo count($fruits); // 3

12. Adding & Removing Elements

$fruits = ["Apple", "Banana"];
array_push($fruits, "Orange");
array_pop($fruits);

13. Merging Arrays

$arr1 = ["Red", "Green"];
$arr2 = ["Blue", "Yellow"];
$merged = array_merge($arr1, $arr2);

14. Splitting & Slicing Arrays

$numbers = [1, 2, 3, 4, 5];
$slice = array_slice($numbers, 1, 3);

15. PHP Arrays and Strings

$str = "red,green,blue";
$arr = explode(",", $str);
$newStr = implode("-", $arr);

16. Arrays with Forms and User Input

if (isset($_POST['hobbies'])) {
    foreach ($_POST['hobbies'] as $hobby) {
        echo $hobby . "<br>";
    }
}

17. Arrays in Database Queries

When fetching results from MySQL:

$result = mysqli_query($conn, "SELECT * FROM users");
while ($row = mysqli_fetch_assoc($result)) {
    print_r($row);
}

18. Arrays in JSON and APIs

$json = '{"name":"John","age":30}';
$array = json_decode($json, true);
echo $array["name"]; // John

19. Multidimensional Array Deep Dive

Example:

$marks = [
    "John" => ["Math" => 90, "Science" => 85],
    "Alice" => ["Math" => 95, "Science" => 80]
];
echo $marks["John"]["Math"]; // 90

20. Nested Arrays and Loops

$matrix = [
    [1, 2, 3],
    [4, 5, 6]
];
foreach ($matrix as $row) {
    foreach ($row as $col) {
        echo $col . " ";
    }
    echo "<br>";
}

21. Performance Tips with Arrays

• Use foreach instead of for for better performance
• Avoid repeated count() calls in loops
• Use isset() for key checks instead of in_array() when possible

22. Best Practices for Arrays

• Use meaningful keys in associative arrays
• Avoid deep nesting (hard to maintain)
• Use array functions for readability

23. Common Mistakes in Arrays

• Using wrong keys
• Forgetting to check if key exists
• Mixing indexed and associative arrays unnecessarily

24. Real-World Examples of PHP Arrays

• Building a shopping cart
• Handling user sessions
• Rendering dynamic menus
• Processing form data
• Storing API responses

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Related topic

• PHP Data Types
• PHP Operators
• PHP Loops
• PHP Functions

Frequently Asked Questions (FAQ)

Q1: What are the types of arrays in PHP?
A: Indexed arrays, associative arrays, and multidimensional arrays.

Q2: Which loop is best for arrays?
A: foreach loop is the best for arrays.

Q3: How to check if a key exists in an array?
A: Use array_key_exists() or isset().

Q4: How to convert a string to an array?
A: Use explode() function.

Q5: How to convert an array to a string?
A: Use implode() function.