# PHP 5 Data Types

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## PHP Data Types

Variables can store data of different types, and different data types can do different things.

PHP supports the following data types:

- String
- Integer
- Float (floating point numbers - also called double)
- Boolean
- Array
- Object
- NULL
- Resource

## PHP String

A string is a sequence of characters, like "Hello world!".

A string can be any text inside quotes. You can use single or double quotes:

## Example

<?php
$x = "Hello world!";
$y = 'Hello world!';
echo $x;
echo "<br>";
echo $y;
?>
Run example »

## PHP Integer

An integer is a whole number (without decimals). It is a number between -2,147,483,648 and +2,147,483,647.

Rules for integers:

- An integer must have at least one digit (0-9)
- An integer cannot contain comma or blanks
- An integer must not have a decimal point
- An integer can be either positive or negative
- Integers can be specified in three formats: decimal (10-based), hexadecimal (16-based - prefixed with 0x) or octal (8-based - prefixed with 0)

In the following example $x is an integer. The PHP var_dump() function returns the data type and value:

## Example

<?php
$x = 5985;
var_dump($x);
?>
Run example »

## PHP Float

A float (floating point number) is a number with a decimal point or a number in exponential form.

In the following example $x is a float. The PHP var_dump() function returns the data type and value:

## Example

<?php
$x = 10.365;
var_dump($x);
?>
Run example »

## PHP Boolean

A Boolean represents two possible states: TRUE or FALSE.

$x = true;
$y = false;

Booleans are often used in conditional testing. You will learn more about conditional testing in a later chapter of this tutorial.

## PHP Array

An array stores multiple values in one single variable.

In the following example $cars is an array. The PHP var_dump() function returns the data type and value:

## Example

<?php
$cars = array("Volvo","BMW","Toyota");
var_dump($cars);
?>
Run example »

You will learn a lot more about arrays in later chapters of this tutorial.

## PHP Object

An object is a data type which stores data and information on how to process that data.

In PHP, an object must be explicitly declared.

First we must declare a class of object. For this, we use the class keyword. A class is a structure that can contain properties and methods:

## Example

<?php
class Car {
function Car() {
$this->model = "VW";
}
}
// create an object
$herbie = new Car();
// show object properties
echo $herbie->model;
?>
Run example »

You will learn more about objects in a later chapter of this tutorial.

## PHP NULL Value

Null is 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.

Tip: If a variable is created without a value, it is automatically assigned a value of NULL.

Variables can also be emptied by setting the value to NULL:

## Example

<?php
$x = "Hello world!";
$x = null;
var_dump($x);
?>
Run example »

## PHP Resource

The special resource type is not an actual data type. It is the storing of a reference to functions and resources external to PHP.

A common example of using the resource data type is a database call.

We will not talk about the resource type here, since it is an advanced topic.

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