Regex in PHP between /* & */ for preg-match

Question

I am trying to extract all substrings in a string that is between the strings /* and */. I know this will probably need to be done with regular expressions however I'm having a hard time getting the correct regex since the star character is actually used to symbolise repeated characters. I'm am trying to use the preg-match method in PHP here is what I have come up with so far but I'm not having much luck.

<?php
   $aString = "abcdef/*ghij*/klmn/*opqrs*/tuvwxyz";
   preg_match("/*/.*/", $aString, $anArray);

   for ($i = 0; $i < count($anArray); i++)
      echo $anArray[i] . "\n";
?>

You don't happen to be parsing comment blocks out of PHP source code with this? — Pekka
– Pekka, Commented Aug 14, 2010 at 11:50
I'm trying to build a php code formatter to display php code using HTML — jazzdawg
– jazzdawg, Commented Aug 14, 2010 at 11:52
Did you try your code before posting it here? There are basic mistakes like: i -> $i which php parser should report. — MartyIX
– MartyIX, Commented Aug 14, 2010 at 11:55

Pekka · Accepted Answer · 2010-08-14 11:59:41Z

1

To extract comment sections out of PHP code, use the Tokenizer.

token_get_all() will parse the code, and return an array of elements.

Comments will be represented as T_COMMENT elements.

This has the great advantage of catching all possible ways of having comments in PHP code:

/* This way, */

// This way

# and this way

answered Aug 14, 2010 at 11:59

Pekka

451k150 gold badges990 silver badges1.1k bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

jazzdawg Over a year ago

Thanks I'll have a look into that

Gumbo Over a year ago

More important: It won’t give you false positives like in $str = "/* foo */";

MartyIX · Accepted Answer · 2010-08-14 12:14:02Z

0

Working code:

 $aString = "abcdef/*ghij*/klmn/*opqrs*/tuvwxyz";

 // SIMPLE VERSION WHERE ASTERISK MAY NOT BE IN THE COMMENT
 // \/\* is just escape sequence for /*  
 // [^\*]* - in comment may be whatever except * (asterisk)
 // \*\/ is escape sequence for */
 preg_match_all("#\/\*[^\*]*\*\/#", $aString, $anArray);

 // BETTER VERSION 
 // http://www.regular-expressions.info/refadv.html - for explanation of ?: and ?!  
 preg_match_all("#\/\*" . "((?:(?!\*\/).)*)" . "\*\/#", $aString, $anArray);


 var_dump($anArray); // easier for debugging than for-loop

Output for better version:

array(2) {
  [0]=>
  array(2) {
    [0]=>
    string(8) "/*ghij*/"
    [1]=>
    string(9) "/*opqrs*/"
  }
  [1]=>
  array(2) {
    [0]=>
    string(4) "ghij"
    [1]=>
    string(5) "opqrs"
  }
}

edited Aug 14, 2010 at 12:14

answered Aug 14, 2010 at 11:52

MartyIX

28.8k33 gold badges143 silver badges218 bronze badges

4 Comments

NullUserException Over a year ago

If I put a star somewhere in there (ie: /*gh*ij*) it will fail

MartyIX Over a year ago

@NullUserException: Yes, I was aware of that and I've added new version which should work better.

NullUserException Over a year ago

Why are you escaping the forward slash with \/?

MartyIX Over a year ago

@NullUserException: I simply don't remember which characters need escaping. :-[

Ugo Méda · Accepted Answer · 2010-08-14 11:51:46Z

0

Escape the * to use it, and ad parentheses to capture the content like that : /\*(.*)\*/, and you should use preg_match_all to find all matches in your string.

(and easier than a for, use var_dump($anArray))

answered Aug 14, 2010 at 11:51

Ugo Méda

1,2059 silver badges23 bronze badges

Comments

bcosca · Accepted Answer · 2010-08-14 11:57:49Z

0

$aString = "abcdef/*ghij*/klmn/*opqrs*/tuvwxyz";
preg_match_all("/\/\*(.*?)\*\//", $aString, $anArray,PREG_SET_ORDER);
var_dump($anArray);

answered Aug 14, 2010 at 11:57

bcosca

17.6k5 gold badges43 silver badges51 bronze badges

Comments

John Parker · Accepted Answer · 2010-08-14 11:58:32Z

0

If (as you say in one of the comments) you're attempting to display PHP code in HTML there's actually a built-in function (highlight_file) that does precisely this.

Free free to ignore if you're using this as a learning exercise, etc. :-)

answered Aug 14, 2010 at 11:58

John Parker

54.5k11 gold badges133 silver badges131 bronze badges

Comments

James R · Accepted Answer · 2014-11-20 17:48:57Z

0

I think the regex will be simple as

\/\*.*?\*\/

here's demo of a working code using regular expression tester

http://liveregex.com/WoDbk

answered Nov 20, 2014 at 17:48

James R

115 bronze badges

Collectives™ on Stack Overflow

Regex in PHP between /* & */ for preg-match

6 Answers 6

2 Comments

4 Comments

Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

6 Answers 6

2 Comments

4 Comments

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related