PHP Data Types

Variables can store data of various types, and different data types serve different purposes.

PHP supports the following data types:

• String
• Integer
• Float (floating-point numbers, also known as double)
• Boolean
• Array
• Object
• NULL
• Resource

Getting the Data Type

You can determine the data type of any object by using the var_dump() function.

Example

The var_dump() function provides both the data type and the value.

$x = 5;
var_dump($x);

PHP NULL Value

NULL is a special data type that can hold only one value: NULL.

A variable of data type NULL is one that has no value assigned to it.

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

Variables can also be cleared by setting their value to NULL.

Example

$x = "Hello world!";

$x = null;

var_dump($x);

Change Data Type

If you assign an integer value to a variable, its type will automatically be set to integer.

If you then assign a string to the same variable, its type will change to string.

Example

$x = 5;
var_dump($x);

$x = "Hello";
var_dump($x);

If you want to change the data type of an existing variable without altering its value, you can use casting.

Casting enables you to modify the data type of variables.

Example

$x = 5;

$x = (string) $x;

var_dump($x);

PHP Resource

The special resource type is not a true data type; it refers to a reference to functions and resources outside of PHP.

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