Variables

This is a very basic lesson about PHP variables. We will get back to variables a few more times in further lessons. A variable is a named entity that stores some value. PHP variables should start with $ sign. Consider this example:

$name = 'Anastasia';

echo 'Hello ' . $name;

That will output Hello Anastasia. And there is something new: a dot operator. This operator is used to concatenate (or join) strings. You also could write it like that:

$name = 'Anastasia';
$greeting = 'Hello ' . $name;

echo $greeting;

And that would give You the same result.

You can also store numbers in a variable and do arithmetic operations on them:

$name = 'Anastasia';
$this_year = 2019;
$age = 29;
$birth_year = $this_year - $age;

echo 'My name is ' . $name . ' and my birth year is ' . $birth_year;

Notice that we used a dot operator with numbers, however a dot operator is a string operator. In this case numbers are converted to strings. Also you can do the opposite:

$a = 5;
$b = '10';

echo $a + $b;

In that case the string stored in the variable $b is converted to a number — because we used an arithmetic operation.

There's another syntax for strings — double quotes. Using double quotes gives you additional features you should know about:

$name = 'Anastasia';
$age = 29;

echo "My name is $name and I'm $age years old";

So, when using a double quotes string syntax, you can write variables directly inside a string. There are more features you can use with double quotes string syntax, but we will discuss them later. Still you should prefer a single quotes string syntax unless you really need a double quotes one.