How can I remove text within parentheses with a regex?


Question

I'm trying to handle a bunch of files, and I need to alter then to remove extraneous information in the filenames; notably, I'm trying to remove text inside parentheses. For example:

filename = "Example_file_(extra_descriptor).ext"

and I want to regex a whole bunch of files where the parenthetical expression might be in the middle or at the end, and of variable length.

What would the regex look like? Perl or Python syntax would be preferred.

1
59
3/12/2009 7:18:31 PM

Accepted Answer

s/\([^)]*\)//

So in Python, you'd do:

re.sub(r'\([^)]*\)', '', filename)
97
5/20/2011 10:43:40 AM

The pattern that matches substrings in parentheses having no other ( and ) characters in between (like (xyz 123) in Text (abc(xyz 123)) is

\([^()]*\)

Details:

  • \( - an opening round bracket (note that in POSIX BRE, ( should be used, see sed example below)
  • [^()]* - zero or more (due to the * Kleene star quantifier) characters other than those defined in the negated character class/POSIX bracket expression, that is, any chars other than ( and )
  • \) - a closing round bracket (no escaping in POSIX BRE allowed)

Removing code snippets:

  • JavaScript: string.replace(/\([^()]*\)/g, '')
  • PHP: preg_replace('~\([^()]*\)~', '', $string)
  • Perl: $s =~ s/\([^()]*\)//g
  • Python: re.sub(r'\([^()]*\)', '', s)
  • C#: Regex.Replace(str, @"\([^()]*\)", string.Empty)
  • VB.NET: Regex.Replace(str, "\([^()]*\)", "")
  • Java: s.replaceAll("\\([^()]*\\)", "")
  • Ruby: s.gsub(/\([^()]*\)/, '')
  • R: gsub("\\([^()]*\\)", "", x)
  • Lua: string.gsub(s, "%([^()]*%)", "")
  • Bash/sed: sed 's/([^()]*)//g'
  • Tcl: regsub -all {\([^()]*\)} $s "" result
  • C++ std::regex: std::regex_replace(s, std::regex(R"(\([^()]*\))"), "")
  • Objective-C:
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"\\([^()]*\\)" options:NSRegularExpressionCaseInsensitive error:&error]; NSString *modifiedString = [regex stringByReplacingMatchesInString:string options:0 range:NSMakeRange(0, [string length]) withTemplate:@""];
  • Swift: s.replacingOccurrences(of: "\\([^()]*\\)", with: "", options: [.regularExpression])

Licensed under: CC-BY-SA with attribution
Not affiliated with: Stack Overflow
Icon