Introduction to PHP Data Types

In PHP, data types are used to classify the type of data that a variable can hold. Understanding these data types is crucial for effective PHP programming, ensuring proper handling of data and avoiding errors. PHP supports various data types, each with its unique characteristics and purposes.

1. Integer

Represents whole numbers without decimal points.

<?php
$age = 25;
$quantity = 10;
 echo  $age ;
 echo $quantity ;
?>

2. Float (Floating Point Number or Double)

<?php
$price = 9.99;
$pi = 3.14159;

echo $price . "\n";
echo $pi . "\n";
?>

3. String

<?php
$name = "John Doe";
$message = 'Hello, World!';

echo "Name: " . $name . "\n";
echo "Message: " . $message . "\n";
?>

4. Boolean

<?php
$isTrue = true;
$isFalse = false;

if ($isTrue) {
    echo "The value of isTrue is true.\n";
} else {
    echo "The value of isTrue is false.\n";
}

if ($isFalse) {
    echo "The value of isFalse is true.\n";
} else {
    echo "The value of isFalse is false.\n";
}
?>

5. Array

<?php
$colors = array("red", "green", "blue"); // Step 1
$numbers = [1, 2, 3, 4, 5]; // Step 2

// Printing the contents of the $colors array
echo "Colors array:\n";
foreach ($colors as $color) {
    echo $color . "\n";
}

// Printing the contents of the $numbers array
echo "Numbers array:\n";
foreach ($numbers as $number) {
    echo $number . "\n";
}
?>

6. Object

<?php
class Car {
    public $brand = "Toyota"; // Step 1
    public $model = "Corolla"; // Step 1
}

$carObj = new Car(); // Step 2

// Accessing and printing the object's properties
echo "Car brand: " . $carObj->brand . "\n"; // Output: Car brand: Toyota
echo "Car model: " . $carObj->model . "\n"; // Output: Car model: Corolla
?>

7. Null

<?php
$nullValue = null; // Variable initialization with null

// Checking if the variable is null
if (is_null($nullValue)) {
    echo "The variable \$nullValue is null.\n";
} else {
    echo "The variable \$nullValue is not null.\n";
}

// Checking if the variable is set
if (isset($nullValue)) {
    echo "The variable \$nullValue is set.\n";
} else {
    echo "The variable \$nullValue is not set.\n";
}
?>

8. Resource

<?php
$file = fopen("example.txt", "r"); // Step 1

// Check if the file was successfully opened
if ($file) {
    // Read and output the file's contents
    while (($line = fgets($file)) !== false) {
        echo $line . "\n";
    }
    
    // Check for end-of-file or error
    if (!feof($file)) {
        echo "Error: unexpected fgets() fail\n";
    }
    
    // Close the file
    fclose($file);
} else {
    echo "Error: unable to open file\n";
}
?>

9. Callable

<?php
function sayHello() {
    echo "Hello!";
}

$funcName = "sayHello"; // Step 2

// Calling the function using the variable
if (function_exists($funcName)) {
    $funcName(); // This will call the sayHello() function
} else {
    echo "Function $funcName does not exist.";
}
?>

10. Iterable

<?php
function sayHello() {
    echo "Hello!";
}

$funcName = "sayHello"; // Step 2

// Calling the function using the variable
if (function_exists($funcName)) {
    $funcName(); // This will call the sayHello() function
} else {
    echo "Function $funcName does not exist.";
}
?>