How to remove comments from php regular expression

php regular method to remove comments: 1. Create a PHP sample file and include the comment content; 2. Remove comments through the "highlight_string(removeComment(file_get_contents('./a.php')));" method That’s it.

The operating environment of this article: windows7 system, PHP8 version, DELL G3 computer

Use regular expressions to remove comments in PHP code

Test code

File: a.PHP

<?php
/**
 * 加法计算
 * 测试
 */
// 设定$a的值
$a = 10;
// 设定$b的值
$b = 5;
// 加法
$c = $a + $b;
# 输出结果
echo $c;

File: test.php

echo "源码：<br />";
show_source(&#39;./a.php&#39;);
echo "<hr />去除注释后：<br />";
highlight_string(removeComment(file_get_contents(&#39;./a.php&#39;)));
 
/**
 * 去除PHP代码注释
 * @param string $content 代码内容
 * @return string 去除注释之后的内容
 */
function removeComment($content){
 return preg_replace("/(\/\*.*\*\/)|(#.*?\n)|(\/\/.*?\n)/s", &#39;&#39;, str_replace(array("\r\n", "\r"), "\n", $content));
}

Test output

Execute test .php, the output is as follows:

Regular analysis

(\/\*.*\*\/) 匹配 /* */
(#.*?\n)  匹配 #  遇到第一个回车后结束
(\/\/.*?\n) 匹配 //  遇到第一个回车后结束

The editor of this site will continue to add:

Multi-line comments

<?php
  
$s = &#39;/*aaaa
sss
*/*/&#39;;
  
preg_match(&#39;@/\*.*?\*/@s&#39;, $s, $match);
  
var_dump($match);

Run result

array(1) {
 [0]=>
 string(15) "/*aaaa
sss
*/"
}

Match single line comment

<?php
$str = " 
a = b; //asdf //saf
b = c; //asdf
  ";
$reg = &#39;@\s*//.*$@m&#39;;
  
$res = preg_replace($reg,&#39;&#39;,$str);
  
echo $res;

Output

a = b;
b = c;

Another Lua version

local test = "int x; /* xx */ xx*/ int y; /* y */"
  
function string.gfind(test, patten)
 local i,j = 0,0;
 return function()
  i,j = string.find(test, patten, j+1)
  if(i == nil) then -- end find
   return nil 
  end 
  return string.sub(test, i, j)
 end 
end
  
  
for v in string.gfind(test, "/%*.-%*/") do
 print(v)
end

Output

/* xx */

/* y */

phpstorm regular matching deletes comment lines (replaces comment lines with blank lines)

Use phpstorm to write php and javascript code, It feels good and is very comfortable to use.

I encountered a need. Sometimes when reading the source code of a framework, I want to filter (delete) the comment lines in the source code. If I delete it manually line by line, it will not be scientific enough.

Of course, I thought of the powerful regular expression (regExp regular expression). By writing a regular expression, we can find all the comment lines and replace them with empty ones, which is how we achieve the requirement.

1. ctrl F , enter the regular expression: (\/\/.*$)|(\/\*(.|\s)*?\*\/)

2. ctrl R, do not enter:

3. Click Replace all

but found that this did not fully realize our needs, but only replaced the comment line with a blank line.

So, let’s write another regular expression to match the blank lines and delete them.

1.ctrl F, enter the regular expression: ^\n

2.ctrl R, do not enter

3. Click Replace all

But I found that not all blank lines were deleted. (There are still some blank lines that have not been deleted)

So, let’s continue with a regular matching deletion.

1.ctrl F, enter the regular expression: \s\n

2.ctrl R, do not enter

3. Click Replace all

Okay, here, delete all blank lines. Have fun -:)

Actually, these three steps can be implemented in one step, you can think about it! [Recommended learning: "PHP Video Tutorial"]

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