Notes – Data Types in PHP

In PHP, data types define the kind of data a variable can hold.

PHP is a loosely-typed language, meaning you do not need to declare the data type explicitly.

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Types of Data in PHP

PHP has four main data types:

1. Scalar Data Types:
   • String: Sequence of characters.
   • Integer: Whole numbers (positive or negative).
   • Float (or double): Decimal numbers.
   • Boolean: True or false values.
2. Compound Data Types:
   • Array: Ordered collection of values.
   • Object: Instances of classes.
3. Special Data Types:
   • NULL: Represents no value or an empty variable.
   • Resource: Reference to an external resource (e.g., a database connection).

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Scalar Data Types

1. String

• A sequence of characters.
• Defined using single (') or double (") quotes.

$name = "John";
$greeting = 'Hello!';

2. Integer

• Whole numbers (positive, negative, or zero).

$age = 25;

3. Float (Double)

• Numbers with decimals.

$price = 19.99;

4. Boolean

• Represents either TRUE or FALSE.

$isAdult = true;
$isActive = false;

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Compound Data Types

1. Array

• Ordered collection of values, indexed by numbers or keys.

$colors = array("red", "green", "blue");
$person = ["name" => "John", "age" => 30];

2. Object

• Instances of a class, used for object-oriented programming.

class Car {
    public $model;
    public function drive() {
        echo "Driving the car";
    }
}
$myCar = new Car();
$myCar->drive();

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Special Data Types

1. NULL

• Represents no value or an empty variable.

$emptyVar = null;

2. Resource

• Refers to an external resource, like a database connection.

$file = fopen("file.txt", "r");  // $file is a resource

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Summary of PHP Data Types

Data Type	Example
String	"Hello, World!"
Integer	25
Float	10.5
Boolean	true, false
Array	["apple", "banana", "cherry"]
Object	$person = new Person()
NULL	$var = null
Resource	$file = fopen("file.txt", "r");