I am trying to write a regex for a string which has a format [digit] [to] [digit] eg. 1 to 5 in which if I find a word "to" from a given string i want to extract the number before and after, I have tried this and it's not working.
Pattern p = Pattern.compile("([0-9]+)\\bto\\b([0-9]+)");
Matcher m = p.matcher("1 to 5");
m.find();
System.out.println(m.group(0));
System.out.println(m.group(1));
System.out.println(m.group(2));
Expected o/p
1
to
5
Consider adding a group for the to part.
Also for the space, you want \\s not \\b:
Pattern p = Pattern.compile("([0-9]+)\\s(to)\\s([0-9]+)");
Matcher m = p.matcher("1 to 5");
m.find();
System.out.println(m.group(1));
System.out.println(m.group(2));
System.out.println(m.group(3));
And as said in the comments :
" Group zero denotes the entire pattern"
Is it necessary that you must use regex. If not, you can use String functions.
String s="23 to 34";
String toString="to";
if(s.contains(toString)){
int startIndex=s.indexOf(toString);
int endIndex=startIndex+(toString).length();
String s1=s.substring(0, startIndex); //get the first number
String s2=s.substring(endIndex); //get the second number
System.out.println(s1.trim()); // Removing any whitespaces
System.out.println(toString);
System.out.println(s2.trim();
}
([0-9]+)\\sto\\s([0-9]+)with\sto match whitespaces should workto, don't expect to get it ingroup