Variables can store data of different types, and different data types can do different things.
PHP supports the following data types:
- Float (floating point numbers – also called double)
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:
<?php $x = "Hello world!"; $y = 'Hello world!'; echo $x; echo "<br>"; echo $y; ?>
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:
<?php $x = 5985; var_dump($x); ?>
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 $x = 10.365; var_dump($x); ?>
A Boolean represents two possible states: TRUE or FALSE.
$y = false;
Booleans are often used in conditional testing. You will learn more about conditional testing in a later chapter of this tutorial.
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:
<?php $cars = array("Volvo","BMW","Toyota"); var_dump($cars); ?>
You will learn a lot more about arrays in later chapters of this tutorial.