Comments in PHP

Introduction to Comments in PHP

The word comment itself express its meaning as commenting out something. If we comment on anything in the PHP program file, it will not be compiled with the code. The compiler or the interpreter will simply ignore this. There are various ways we can go with commenting on anything in the PHP programming language. PHP has a single line and multiple line comment options as well. Also, in the single-line comment, we can use the / or # as per our convenience. We should always write the appropriate language in the comment so that anyone who is reviewing that code can read and understand that comment.

Syntax

Again, we can use the comment in the below-mentioned ways in PHP.

Single Line Comment:

// This is a single-line comment
# This is a single-line comment
/*
This is a multiple line comment – line no – 1
This is a multiple line comment – line no – 2
… and so on …
*/
# this is the single-line comment
; this is a PHP.INI style commenting

How does Comments in PHP work?

The moment we write the comment in the code it will be lighter in view comparatively as compared to the actual code. If we have written code and the comment in the same file, in this case, the comment will not be executed while running that PHP file. So let’s see the same with an example.

<?PHP
echo "This is my first PHP Program";
// this is the first program
?>

This will give only ‘This is my first PHP Program’ as an output, not the comment part.

Why we should use comments?

We should use the comment in between the PHP program code to make sure we had enough help comments so that one can easily read and understand the code. In comment, we can also for the purpose of writing the segment of the code, change the date, modification date, modified by, etc. It is highly recommended for a developer to use the comment in the programming code so that things can be understood easily with little or no effort whenever required.

Examples

Now, it’s time to see some quick example the check the behavior of the comment in the program.

Example #1

<?php
echo "This is my first PHP Program";
// this is the first program
?>

Output 

Example #2

Single line comment in the program

Code:

<?php
echo date_default_timezone_get(); //to get the timezone
echo "<br>"; //line brea;
date_default_timezone_set('Asia/Kolkata'); // setting the timezone to Asia/Kolkata
echo date_default_timezone_get(); //to get the timezone
?>

Output 

Example #3

Multi-line comment in the program

Code:

<?php
/*
This is a function that will take time in minutes and will return that in hours and minutes
We use will this function further to test with some examples.
*/
function hoursandmins($minutes, $format = '%01d Hours, %02d Minutes')
{
if ($minutes < 1) {
return;
}else if($minutes<10){
if($minutes==1){
return '0'.$minutes.' Minute';
}
return '0'.$minutes.' Minutes';
}else if($minutes<50){
return $minutes.' Minutes';
}
$hours = floor($minutes / 60);
$minutes = ($minutes % 60);
$format = "";
if($hours>0){
if($hours>1){
$format .= '%01d Hours';
}else{
$format .= '%01d Hour';
}
}
if($hours>0 && $minutes>0){
$format .= ', ';
}
if($minutes>0){
if($minutes>1){
$format .= ' %02d Minutes';
}else{
$format .= ' %01d Minute';
}
}
return sprintf($format, $hours, $minutes);
}
// time to check the time in descriptive form
echo hoursandmins(20);
echo "<br>";
echo hoursandmins(120);
?>

Output 

Any comments written before any function about that function is commonly known as the function documentation. So, in the given scenarios we can say this comment as a function document. This is really nice to use the comment like that. To make the PHP program more robust we have various PHP standards that say we should not use the comment inside the function as we can do the same in the function documentation.

Example #4

Mixed comment

In a PHP program file, we can combine both PHP and HTML. Considering this, we will use the HTML commenting method to comment out the HTML part whenever required, and the PHP comments can be used for the PHP related code as per the business requirements. We can use any kind of PHP comments and the HTML comments in a PHP-HTML file.

Code:

<html>
<body>
<h1>PHP with HTML</h1>
<!-- this is html comment -->
<?php
echo "Hello World!"; // this is PHP comment
?>
</body>
</html>

Output 

Example #5

Single line comment using #

We can use the single line commenting using the # as well. Let’s see an example of the code for the same. We can see this line of commenting is not that much popular. Very few developers use these kinds of comments. This is really recommended for the while commenting for the function documentation or the file level documentation.

Code:

<?php
# $i=10;
# $j=20;
# echo $i + $j;
echo "Hello World!";
# this is PHP comment
?>

Output

Conclusion

A comment is really a call of time in the code. We can use the comment in our PHP program file. This will help us to make the code more understandable. We should use the comment before starting a function or the class as most programming languages have their own code standard. Usually, the comment before any function or the class called the documentation of that function or the class.

Recommended Articles

This is a guide to Comments in PHP. Here we discuss the introduction, How does it work, why we should use comments along with Examples and outputs. You can also go through our other suggested articles to learn more –

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