PHP Comments
Comments in PHP
A comment in PHP code is a line that is not executed as a part of the program. Its only purpose is to be read by someone who is looking at the code.
Comments can be used to:
- Let others understand your code
- Remind yourself of what you did - Most programmers have experienced coming back to their own work a year or two later and having to re-figure out what they did. Comments can remind you of what you were thinking when you wrote the code
- Leave out some parts of your code
PHP supports several ways of commenting:
Example
Syntax for comments in PHP code:
// This is a single-line comment
# This is also a single-line comment
/* This is a
multi-line comment */
Single Line Comments
Single line comments start with //
.
Any text between //
and the end of the line will be ignored (will not be executed).
You can also use #
for single line comments, but in this tutorial we will use //
.
The following examples uses a single-line comment as an explanation:
Example
A comment before the code:
// Outputs a welcome message:
echo "Welcome Home!";
Example
A comment at the end of a line:
echo "Welcome Home!"; // Outputs a welcome message
Comments to Ignore Code
We can use comments to prevent code lines from being executed:
Example
Do not display a welcome message:
// echo "Welcome Home!";
Multi-line Comments
Multi-line comments start with /*
and end with */
.
Any text between /*
and */
will be ignored.
The following example uses a multi-line comment as an explanation:
Example
Multi-line comment as an explanation:
/*
The next statement will
print a welcome message
*/
echo "Welcome Home!";
Multi-line Comments to Ignore Code
We can use multi-line comments to prevent blocks of code from being executed:
Example
Multi-line comment to ignore code:
/*
echo "Welcome to my home!";
echo "Mi casa su casa!";
*/
echo "Hello!";
Comments in the Middle of the Code
The multi-line comment syntax can also be used to prevent execution of parts inside a code-line:
Example
The + 15
part will be ignored in the calculation:
$x = 5 /* + 15 */ + 5;
echo $x;