Question

I have text file which has text with newline char like this. I read that text file into a String

random Text
State v. USA
some more text
USA v.
NY
Some more text
USA
v.LA ,  MN v. ND
USA vs. MN

I want to know offset (i.e. starting and ending char index) of patterns like [Some word starting with cap] v. [Some word starting with cap]

Or
[Some word starting with cap] vs. [Some word starting with cap]

For above example
“State v. USA” => Start=11 and End=22

“USA v.
NY” => Start=36 and End=45

I started with something like this http://rubular.com/r/T7Ii2WDADw which is not covering all cases .

So, the program could return a Map where key is Start+”,”+End and value is actual text like “State v. USA”

Answer 1

To cover both the cases you need to use this regex.

\w+\s((v.)|(vs.))\s\w+

In java code.

import java.util.regex.Pattern;
import java.util.regex.Matcher;

public class Testapp {

public static void main(String[] args) {
String text = "USA v. Russia \n Some other text \n India vs. Aus";
String regex="\\w+\\s((v.)|(vs.))\\s\\w+";
Pattern p = Pattern.compile(regex);
Matcher matcher = p.matcher(text);

while (matcher.find()) {
    System.out.println(matcher.group()+ ":" +"start =" + matcher.start() + " end = " + matcher.end());
}
}
}

Output:

Starting & ending index ofUSA v. Russia:start=0 end = 13
Starting & ending index ofIndia vs. Aus:start=34 end = 47