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PHP Syntax

If you pay attention PHP syntax it is really easy to understand and follow, we call syntax the structure of statements in a computer language.

You can easily identify PHP code as it must live within the <?php and ?> (opening and closing tags) as well as written in a .php file.

On the following statement example, our code is written in <?php and it should echo (output) a string. The ; at the end terminates this statement and since we are only using PHP we can omit the ?> closing tag as there’s no other language following.

I have to mention now just for general knowledge that PHP syntax is semi case sensitive. This means that on some occasions it cares about being case sensitive and on some others it does not. For example statements like if, while, for & functions, as well as classes, are case insensitive while variables are case sensitive.

echo 'Welcome to the PHP Basics tutorial!';

// This would output "PHPBasics".
echo 'PHP';
eChO 'Basics';

// But this would output just "PHP".
$say    = 'PHP';
$basics = 'Basics';

echo $say . $bAsIcS;

Even though some aspects of the language are case insensitive it is good practice to use standards in your code. Try to have consistency i.e. for variables use lowercase letters and capitalize your classes. This consistency will help you as well as the code will be easier to be read by others.

Comments in PHP Syntax

I've always been a fan of spacious and well-commented code. It helps to easily remember why it was written and what its purpose is.

I'm not going to debate "tabs" vs "spaces". I personally use tabs, but that's up to you. What I will strongly advise is adding an empty line when it's needed and write comments as much as possible. This gives your code a more human-readable form.

Let's see the types of comments that you can use!

For single lines, you can use either // or # at the start of each line and for multi-line comments as well as "commenting out" parts of code you can start with /* and end with */.

// This is a single line comment.

# This is a single line comment as well!

	This is an example of
	a multi-line comment.

 * This is what we call
 * a "block comment".

// This will output "15" as the "+ 2" has been commented out.
$mystring = 10 /* + 2 */ + 5;

echo $mystring;

Extra Tips

WordPress community has it's own PHP Coding Standards that you can apply to your syntax.

You can set up your coding environment with extra helping tools you can also use PHP Code Sniffer. WordPress Coding Standards are additional rules for PHPCS to automatically find issues with your syntax.