PHP – Data Types

 

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

 

<!DOCTYPE html>
<html>
<body>

<?php
$x = “Robert”;
$y = ‘Karamagi’;

echo $x;
echo “<br>”;
echo $y;
?>

</body>
</html>

 

Output

 

 

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 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

 

<!DOCTYPE html>
<html>
<body>

<?php
$x = 8080;
var_dump($x);
?>

</body>
</html>

 

Output

 

 

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

 

<!DOCTYPE html>
<html>
<body>

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

</body>
</html>

 

Output

 

 

PHP Boolean

 

A Boolean represents two possible states: TRUE or FALSE.

$x = true;
$y = false;

Booleans are often used in conditional testing.

 

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

 

<!DOCTYPE html>
<html>
<body>

<?php
$cars = array(“Volvo”,”BMW”,”Toyota”);
var_dump($cars);
?>

</body>
</html>

 

Output

 

 

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

 

<!DOCTYPE html>
<html>
<body>

<?php
class Car {
function Car() {
$this->model = “VW”;
}
}
// create an object
$herbie = new Car();

// show object properties
echo $herbie->model;
?>

</body>
</html>

 

Output

 

 

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

 

<!DOCTYPE html>
<html>
<body>

<?php
$x = “Hello world!”;
$x = null;
var_dump($x);
?>

</body>
</html>

 

Output

 

 

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.