Matcher doesn't return the matched regex, instead returns whole string in group(0) (Java)

Question

The problem I'm facing is that upon following the question at this link, Using Regular Expressions to Extract a Value in Java, I am unable to extract the correct group of the String

Pattern p = Pattern.compile("I have .*");
Matcher m = p.matcher("I have apples");

if(m.find()){
    System.out.println(m.group(0));
}

What I get:

I have apples

What I want to get:

apples

I've tried asking for m.group(1) as well but it throws me an exception.

How should I go about this?

You need to place what you need as the result into a capturing group. Something like `"I have (\w+)"` — PM 77-1, Feb 08 '22 at 17:17

score 3 · Accepted Answer · answered Feb 08 '22 at 17:23

3

You have to define a capturing group to get m.group(...) work correctly.

Change your pattern to

Pattern p = Pattern.compile("I have (.*)");

m.group(0) 'denotes the entire pattern' m.group(1) now returns the expected 'apple'

answered Feb 08 '22 at 17:23

blafoo

1 Answers1