Notes can come in all sorts of shapes and sizes. They vary, and their uses are completely up to the person writing the code. However, I try to keep things consistent in my code that way it's easy for the next person to read. So something like this might help...
<?php
//======================================================================
// CATEGORY LARGE FONT
//======================================================================
//-----------------------------------------------------
// Sub-Category Smaller Font
//-----------------------------------------------------
/* Title Here Notice the First Letters are Capitalized */
# Option 1
# Option 2
# Option 3
/*
* This is a detailed explanation
* of something that should require
* several paragraphs of information.
*/
// This is a single line quote.
?>
주석
PHP는 'C', 'C++', Unix 쉘 형식(펄 형식)의 주석(comment)형태를 지원한다. 예를 들면:
<?php
echo 'This is a test'; // 한줄짜리 c++ 스타일 주석
/* 여러줄의 주석
이줄까지 주석처리 된다 */
echo 'This is yet another test';
echo 'One Final Test'; # 쉘 형식의 한줄짜리 주석
?>
"한 줄" 주석 형식은 줄의 끝까지나 PHP 코드의 현재 블록까지 중, 먼저 오는 부분까지만 주석으로 처리합니다. 이는 // ... ?>나 # ... ?> 뒤에 오는 HTML 코드가 출력됨을 의미합니다: ?>는 PHP 모드를 종료하고 HTML 모드로 돌아가게 하므로, //나 #은 영향을 주지 않습니다. asp_tags 설정 지시어가 켜져 있으면, // %>나 # %>에도 동일하게 적용됩니다. 그러나, </script> 태그는 한 줄 주석에서 PHP 모드를 종료하지 않습니다.
<h1>This is an <?php # echo 'simple';?> example.</h1>
<p>The header above will say 'This is an example'.</p>
'C' 형식 주석은 첫 */에서 종료합니다. 그러므로 'C' 형식 주석을 중첩하지 않아야 합니다. 이는 큰 코드 블럭을 주석처리 하려고 할 경우에 자주 발생하는 실수입니다.
<?php
/*
echo 'This is a test'; /* 이 주석은 문제가 발생합니다 */
*/
?>
add a note
User Contributed Notes 11 notes
J. Prettyman ¶
10 years ago
M Spreij ¶
19 years ago
A nice way to toggle the commenting of blocks of code can be done by mixing the two comment styles:
<?php
//*
if ($foo) {
echo $bar;
}
// */
sort($morecode);
?>
Now by taking out one / on the first line..
<?php
/*
if ($foo) {
echo $bar;
}
// */
sort($morecode);
?>
..the block is suddenly commented out.
This works because a /* .. */ overrides //. You can even "flip" two blocks, like this:
<?php
//*
if ($foo) {
echo $bar;
}
/*/
if ($bar) {
echo $foo;
}
// */
?>
vs
<?php
/*
if ($foo) {
echo $bar;
}
/*/
if ($bar) {
echo $foo;
}
// */
?>
aetonsi ¶
2 years ago
As of php 8, single line comments starting exactly with "#[" have a special meaning: they are treated as "attributes", and they must respect the expected syntax. See: https://www.php.net/manual/en/language.attributes.php
So the following code throws an error in php 8+, while it is perfectly valid in php <8:
<?php
#[~~my super cool comment~~~]
?>
To be safe, just always use "//" comments instead of "#". Maybe in the future there will be other special meanings for the "#" comments, who knows.
magnesium dot oxide dot play+php at gmail dot com ¶
11 years ago
It is worth mentioning that, HTML comments have no meaning in PHP parser. So,
<!-- comment
<?php echo some_function(); ?>
-->
WILL execute some_function() and echo result inside HTML comment.
hcderaad at wanadoo dot nl ¶
19 years ago
Comments in PHP can be used for several purposes, a very interesting one being that you can generate API documentation directly from them by using PHPDocumentor (http://www.phpdoc.org/).
Therefor one has to use a JavaDoc-like comment syntax (conforms to the DocBook DTD), example:
<?php
/**
* The second * here opens the DocBook commentblock, which could later on<br>
* in your development cycle save you a lot of time by preventing you having to rewrite<br>
* major documentation parts to generate some usable form of documentation.
*/
?>
Some basic html-like formatting is supported with this (ie <br> tags) to create something of a layout.
J Lee ¶
18 years ago
MSpreij (8-May-2005) says /* .. */ overrides //
Anonymous (26-Jan-2006) says // overrides /* .. */
Actually, both are correct. Once a comment is opened, *everything* is ignored until the end of the comment (or the end of the php block) is reached.
Thus, if a comment is opened with:
// then /* and */ are "overridden" until after end-of-line
/* then // is "overridden" until after */
Steve ¶
20 years ago
Be careful when commenting out regular expressions.
E.g. the following causes a parser error.
I do prefer using # as regexp delimiter anyway so it won't hurt me ;-)
<?php
/*
$f->setPattern('/^\d.*/');
*/
?>
theblazingangel at aol dot com ¶
17 years ago
it's perhaps not obvious to some, but the following code will cause a parse error! the ?> in //?> is not treated as commented text, this is a result of having to handle code on one line such as <?php echo 'something'; //comment ?>
<?php
if(1==1)
{
//?>
}
?>
i discovered this "anomally" when i commented out a line of code containing a regex which itself contained ?>, with the // style comment.
e.g. //preg_match('/^(?>c|b)at$/', 'cat', $matches);
will cause an error while commented! using /**/ style comments provides a solution. i don't know about # style comments, i don't ever personally use them.
jballard at natoga dot com ¶
14 years ago
Comments do NOT take up processing power.
So, for all the people who argue that comments are undesired because they take up processing power now have no reason to comment ;)
<?php
// Control
echo microtime(), "<br />"; // 0.25163600 1292450508
echo microtime(), "<br />"; // 0.25186000 1292450508
// Test
echo microtime(), "<br />"; // 0.25189700 1292450508
# TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST
# .. Above comment repeated 18809 times ..
echo microtime(), "<br />"; // 0.25192100 1292450508
?>
They take up about the same amount of time (about meaning on a repeated testing, sometimes the difference between the control and the test was negative and sometimes positive).
Wolfsbay at ya dot ru ¶
14 years ago
If you are using editor with code highlight, it’s much easier to notice error like /* */ */.
fun at nybbles dot com ¶
18 years ago
a trick I have used in all languages to temporarily block out large sections (usually for test/debug/new-feature purposes), is to set (or define) a var at the top, and use that to conditionally comment the blocks; an added benefit over if(0) (samuli's comment from nov'05) is that u can have several versions or tests running at once, and u dont require cleanup later if u want to keep the blocks in: just reset the var.
personally, I use this more to conditionally include code for new feature testing, than to block it out,,,, but hey, to each their own :)
this is also the only safe way I know of to easily nest comments in any language, and great for multi-file use, if the conditional variables are placed in an include :)
for example, placed at top of file:
<?php $ver3 = TRUE;
$debug2 = FALSE;
?>
and then deeper inside the file:
<?php if ($ver3) {
print("This code is included since we are testing version 3");
}
?>
<?php if ($debug2) {
print("This code is 'commented' out");
}
?>
