Table of Contents:
PHP Arrays – Complete Tutorial with Examples
Welcome to phponline.in, your go-to place for learning PHP step by step.
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
- Introduction to PHP Arrays
- Why Use Arrays in PHP?
- Types of Arrays in PHP
- Indexed Arrays
- Associative Arrays
- Multidimensional Arrays
- Creating Arrays in PHP
- Accessing Array Elements
- Modifying Arrays in PHP
- Looping Through Arrays
- Array Functions in PHP
- Sorting Arrays
- Searching in Arrays
- Array Length and Count
- Adding & Removing Elements
- Merging Arrays
- Splitting & Slicing Arrays
- PHP Arrays and Strings
- Arrays with Forms and User Input
- Arrays in Database Queries
- Arrays in JSON and APIs
- Multidimensional Array Deep Dive
- Nested Arrays and Loops
- Performance Tips with Arrays
- Best Practices for Using Arrays
- Common Mistakes in Arrays
- 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:
- Indexed Arrays – Use numeric indexes
- Associative Arrays – Use named keys
- 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
foreachinstead offorfor better performance - Avoid repeated
count()calls in loops - Use
isset()for key checks instead ofin_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
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.