Java and RegEx .. how to apply

Question

I'm attempting to do the following:

            Scanner scanner = new Scanner(file);
            StringBuilder sb = new StringBuilder();
            while (scanner.hasNextLine()) {
                sb.append(scanner.nextLine() + "\n");
            }

            String data = sb.toString();

            Pattern p = Pattern.compile("\b[ABD-Z]*C[ABD-Z]*\b");
            Matcher m = p.matcher(data);

            String a = m.group();

How do I access the results of m? Why is my RegEx not working?

I have tried escaping backslashes already.

It works on http://www.gskinner.com/RegExr/ but I can't get any output from Java.

Please help≥.. thanks.

This is already the third posting today for the same homework. You need to write \\b instead of \b unless you mean the backspace character. — maaartinus
– maaartinus, Commented Jan 20, 2011 at 16:29
Yes, embarrasing,... I guess I after spending a long time experimenting I just got annoyed. I still have plenty more work, but I won't use SO for it. Just needed a starter for 10. : ) — Alex
– Alex, Commented Jan 20, 2011 at 17:24

josh.trow · Accepted Answer · 2011-01-20 16:27:08Z

1

You need to use m.find() or m.match() most likely in a while loop.

while (m.find()) {
 do something with m.group()
}

answered Jan 20, 2011 at 16:27

josh.trow

4,90123 silver badges31 bronze badges

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

Comments

lweller · Accepted Answer · 2011-01-20 16:26:48Z

1

yes you have to escape your backslashes to have a valid java string

you have to call m.find() before m.group()

answered Jan 20, 2011 at 16:26

lweller

11.3k3 gold badges37 silver badges39 bronze badges

2 Comments

Alex Over a year ago

Ok and how do I deal with multiple results?

lweller Over a year ago

as proposed by josh.trow simply loop until m.find() returns false

Mike Samuel · Accepted Answer · 2011-01-20 16:26:53Z

1

You need to use \\b instead of \b since the latter is a backspace and call m.find() if you're trying to match a substring or m.match() to match the whole string before calling group().

answered Jan 20, 2011 at 16:26

Mike Samuel

121k30 gold badges230 silver badges255 bronze badges

Collectives™ on Stack Overflow

Java and RegEx .. how to apply

3 Answers 3

Comments

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related