Regular Expression for Finding and Deleting comments

[MRAB]

On 04/01/2011 17:11, Jeremy wrote:
> I am trying to write a regular expression that finds and deletes (replaces with nothing) comments in a string/file.  Comments are defined by the first non-whitespace character is a 'c' or a dollar sign somewhere in the line.  I want to replace these comments with nothing which isn't too hard.  The trouble is, the comments are replaced with a new-line; or the new-line isn't captured in the regular expression.
>
> Below, I have copied a minimal example.  Can someone help?
>
> Thanks,
> Jeremy
>
>
> import re
>
> text = """ c
> C - Second full line comment (first comment had no text)
> c   Third full line comment
>    F44:N 2    $ Inline comments start with dollar sign and go to end of line"""
>
> commentPattern = re.compile("""
>      (^\s*?c\s*?.*?|             # Comment start with c or C
>      \$.*?)$\n                           # Comment starting with $
>      """, re.VERBOSE|re.MULTILINE|re.IGNORECASE)
>
Part of the problem is that you're not using raw string literals or
doubling the backslashes.

Try soemthing like this:

commentPattern = re.compile(r"""
     (^[ \t]*c.*\n|              # Comment start with c or C
     [ \t]*\$.*)                 # Comment starting with $
     """, re.VERBOSE|re.MULTILINE|re.IGNORECASE)

> found = commentPattern.finditer(text)
>
> print("\n\nCard:\n--------------\n%s\n------------------" %text)
>
> if found:
>     print("\nI found the following:")
>     for f in found: print(f.groups())
>
> else:
>     print("\nNot Found")
>
> print("\n\nComments replaced with ''")
> replaced = commentPattern.sub('', text)
> print("--------------\n%s\n------------------" %replaced)
>