Question

I am trying to solve a fairly easy problem but can’t quite figure out how to use regexs properly. I want to extract any words from a text file between (parentheses). This was the sort of attempt I have going. Any shove in the right direction would be appreciated!!

public class Reader {

    public static void main(String[] args) {
        List<String> matchList = new ArrayList<String>();
        Pattern regex = Pattern.compile("\\{([^}]*)\\}");

        try{
            BufferedReader bufferedReader = new BufferedReader(new FileReader("test2.txt"));

            while(bufferedReader.readLine()!=null)
            {
                String parseMe = bufferedReader.readLine();

                Matcher regexMatcher = regex.matcher(parseMe);

                while (regexMatcher.find()) 
                {
                    matchList.add(regexMatcher.group());
                } 
            }
            System.out.println(matchList);
        }catch(IOException e){};
    }
}

Answer 1

The regex string should (at least) be "[({\\[].*?[\\]})]" The outer square brackets are regex syntax — you are defining a character class to look for. It’s not perfect and a completely correct solution is impossible in Java regex (you can’t account for nested brackets). But there’s a start 🙂 BTW you may find it useful to experiment with the regex using Eclipse Find. It’s even got a great content assist.