Java matcher unable to finding last group

Question

I'm trying regex after a long time. I'm not sure if the issue is with regex or the logic.

String test = "project/components/content;contentLabel|contentDec"; String regex = "(([A-Za-z0-9-/]*);([A-Za-z0-9]*))"; Map<Integer, String> matchingGroups = new HashMap<>(); Pattern pattern = Pattern.compile(regex); Matcher matcher = pattern.matcher(test); //System.out.println("Input: " + test + "\n"); //System.out.println("Regex: " + regex + "\n"); //System.out.println("Matcher Count: " + matcher.groupCount() + "\n"); if (matcher != null && matcher.find()) { for (int i = 0; i < matcher.groupCount(); i++) { System.out.println(i + " -> " + matcher.group(i) + "\n"); } }

I was expecting the above to give me the output as below:

0 -> project/components/content;contentLabel|contentDec 1 -> project/components/content 2 -> contentLabel|contentDec

But when running the code the group extractions are off.

Any help would be really appreciated.

Thanks!

On executing this, I'm still unable to get the last group information. This is the output I see now -------->> 0 -> project/components/content;contentLabel|contentDec 1 -> project/components/content — phemanthkumar28
– phemanthkumar28, Commented Mar 27, 2020 at 2:28

Nick · Accepted Answer · 2020-03-27 02:44:05Z

You have a few issues:

You're missing | in your second character class.
You have an unnecessary capture group around the whole regex.
When outputting the groups, you need to use <= matcher.groupCount() because matcher.group(0) is reserved for the whole match, so your capture groups are in group(1) and group(2).

This will work:

String test = "project/components/content;contentLabel|contentDec"; String regex = "([A-Za-z0-9-/]*);([A-Za-z0-9|]*)"; Pattern pattern = Pattern.compile(regex); Matcher matcher = pattern.matcher(test); if (matcher != null && matcher.find()) { for (int i = 0; i <= matcher.groupCount(); i++) { System.out.println(i + " -> " + matcher.group(i) + "\n"); } }

Perfect! This worked. Great explanation, especially the 3rd point. Thank you!

Collectives™ on Stack Overflow

Java matcher unable to finding last group

1 Answer 1

1 Comment

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Related