How many data types are in php?

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

$x = "Hello world!";
$y = 'Hello world!';

echo $x;
echo "
";
echo $y;
?>

Try it Yourself »

PHP Integer

An integer data type is a non-decimal number between -2,147,483,648 and 2,147,483,647.

Rules for integers:

• An integer must have at least one digit
• An integer must not have a decimal point
• An integer can be either positive or negative
• Integers can be specified in: decimal (base 10), hexadecimal (base 16), octal (base 8), or binary (base 2) notation

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

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:

PHP Boolean

A Boolean represents two possible states: TRUE or 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

$cars = array("Volvo","BMW","Toyota");
var_dump($cars);
?>

Try it Yourself »

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

PHP Object

Classes and objects are the two main aspects of object-oriented programming.

A class is a template for objects, and an object is an instance of a class.

When the individual objects are created, they inherit all the properties and behaviors from the class, but each object will have different values for the properties.

Let's assume we have a class named Car. A Car can have properties like model, color, etc. We can define variables like $model, $color, and so on, to hold the values of these properties.

When the individual objects (Volvo, BMW, Toyota, etc.) are created, they inherit all the properties and behaviors from the class, but each object will have different values for the properties.

If you create a __construct() function, PHP will automatically call this function when you create an object from a class.

Example

class Car {
  public $color;
  public $model;
  public function __construct($color, $model) {
    $this->color = $color;
    $this->model = $model;
  }
  public function message() {
    return "My car is a " . $this->color . " " . $this->model . "!";
  }
}

$myCar = new Car("black", "Volvo");
echo $myCar -> message();
echo "
";
$myCar = new Car("red", "Toyota");
echo $myCar -> message();
?>

Try it Yourself »

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:

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.

Data Types define the type of data a variable can store. PHP allows eight different types of data types. All of them are discussed below. There are pre-defined, user-defined, and special data types.

The predefined data types are:

• Boolean
• Integer
• Double
• String

The user-defined (compound) data types are:

• Array
• Objects

The special data types are:

• NULL
• resource

The first five are called simple data types and the last three are compound data types: 
 

1. Integer: Integers hold only whole numbers including positive and negative numbers, i.e., numbers without fractional part or decimal point. They can be decimal (base 10), octal (base 8), or hexadecimal (base 16). The default base is decimal (base 10). The octal integers can be declared with leading 0 and the hexadecimal can be declared with leading 0x. The range of integers must lie between -2^31 to 2^31. 

Example: 

PHP

$deci1 = 50;

$deci2 = 654;

$octal1 = 07;

$octal = 0x45;

$sum = $deci1 + $deci2;

echo $sum;

echo "\n\n";

var_dump($sum)

?>

2. Double: Can hold numbers containing fractional or decimal parts including positive and negative numbers or a number in exponential form. By default, the variables add a minimum number of decimal places. The Double data type is the same as a float as floating-point numbers or real numbers.

Example: 

PHP

$val1 = 50.85;

$val2 = 654.26;

$sum = $val1 + $val2;

echo $sum;

echo "\n\n";

var_dump($sum)

?>

Output

705.11

float(705.11)

3. String: Hold letters or any alphabets, even numbers are included. These are written within double quotes during declaration. The strings can also be written within single quotes, but they will be treated differently while printing variables. To clarify this look at the example below. 
 

Example: 

PHP

$name = "Krishna";

echo "The name of the Geek is $name \n";

echo 'The name of the geek is $name ';

echo "\n\n";

var_dump($name)

?>

Output

The name of the Geek is Krishna 
The name of the geek is $name 

string(7) "Krishna"

4. Boolean: Boolean data types are used in conditional testing. Hold only two values, either TRUE(1) or FALSE(0). Successful events will return true and unsuccessful events return false. NULL type values are also treated as false in Boolean. Apart from NULL, 0 is also considered false in boolean. If a string is empty then it is also considered false in boolean data type. 

Example:   

PHP

if(TRUE)

    echo "This condition is TRUE";

if(FALSE)

    echo "This condition is not TRUE";

?>

Output

This condition is TRUE

5. Array: Array is a compound data type that can store multiple values of the same data type. Below is an example of an array of integers. It combines a series of data that are related together.
  

PHP

$intArray = array( 10, 20 , 30);

echo "First Element: $intArray[0]\n";

echo "Second Element: $intArray[1]\n";

echo "Third Element: $intArray[2]\n\n";

var_dump($intArray);

?>

Output

First Element: 10
Second Element: 20
Third Element: 30

array(3) {
  [0]=>
  int(10)
  [1]=>
  int(20)
  [2]=>
  int(30)
}

We will discuss arrays in detail in further articles. 
 

6. Objects: Objects are defined as instances of user-defined classes that can hold both values and functions and information for data processing specific to the class. This is an advanced topic and will be discussed in detail in further articles. When the objects are created, they inherit all the properties and behaviours from the class, having different values for all the properties.

This is an example of Object Data Type!