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.