# PHP Data Types

Variables can store data of different types, and different data types can do different things. PHP supports the following data types:

---

## 1. Scalar Types
These types hold a single value.

*   **String:** A sequence of characters, like "Hello world!".
*   **Integer:** A non-decimal number between -2,147,483,648 and 2,147,483,647.
*   **Float (Double):** A number with a decimal point or a number in exponential form.
*   **Boolean:** Represents two possible states: `true` or `false`.

```php
$x = "Hello world!"; // String
$y = 5985;           // Integer
$z = 10.365;         // Float
$isActive = true;    // Boolean
```

## 2. Compound Types
These types can hold multiple values.

*   **Array:** Stores multiple values in one single variable.
*   **Object:** Instances of user-defined classes that can store both values and functions.

```php
$cars = array("Volvo", "BMW", "Toyota"); // Array

class Car {
  public $color;
  public $model;
  public function __construct($color, $model) {
    $this->color = $color;
    $this->model = $model;
  }
}
$myCar = new Car("black", "Volvo"); // Object
```

## 3. Special Types

*   **NULL:** A special data type which can have only one value: `NULL`. A variable of data type NULL is a variable that has no value assigned to it.
*   **Resource:** Not an actual data type. It is the storing of a reference to functions and resources external to PHP (e.g., a database connection).

## 4. Checking Data Type
The `var_dump()` function returns the data type and value.

```php
$x = 5;
var_dump($x); // int(5)
```

[[programming/php/php]] [[programming/php/php-arrays]] [[programming/php/php-classes]]