Variables

All PHP variables must starts with $ and follow by a name combined with any of characters:

$my_var;

Note: a variable name can not starts with a number. For example, "$3men" is incorrect.

We can declare and define a variable something like that:

$my_var = "I love PHP";

Much easier than Java, you don't have to be careful about the types of variables in PHP. Any variable can be an integer, floating-point number, string, object, or an array:

$my_var1 = 240;          // integer
$my_var2 = 1.40;         // floateing-point number
$my_var3 = "I love PHP"; //string

Note: a string must begin and end with a pair of either single (' ') or double (" ") quotes.

We can combine the values of two variables:

$my_var1 = "I love ";
$my_var2 = "$my_var1 PHP";
echo $my_var2;

The output is:

I love PHP

To take two strings and combine them into a single string, we use the period operator ("."). For example:

<?php

     $a = "Hello, ";
     $b = "welcome to my website!";

     echo $a . $b;
?>