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Regular Expression "(re)" Sub-Expression in Java
The subexpression/metacharacter “( )” groups the regular expressions and remembers the matched text.
Example 1
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Example {
public static void main( String args[] ) {
String input = "Hello how are you welcome to Tutorialspoint";
String regex = "H(ell|ow)";
//Compiling the regular expression
Pattern pattern = Pattern.compile(regex);
//Retrieving the matcher object
Matcher matcher = pattern.matcher(input);
if(matcher.find()) {
System.out.println("Match found");
} else {
System.out.println("Match not found");
}
}
}Output
Match found
Example 2
In the following example, we are trying to match a sentence with digits in it −
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class PatternExample {
public static void main(String[] args) {
System.out.println("Enter input string: ");
Scanner sc = new Scanner(System.in);
String input = sc.nextLine();
//Regular expression using groups
String regex = "(?:.*)(\d+)(.*)";
//Creating a pattern object
Pattern pattern = Pattern.compile(regex);
//Creating a Matcher object
Matcher matcher = pattern.matcher(input);
boolean bool = matcher.matches();
if(bool) {
System.out.println("Match found");
} else {
System.out.println("Match not found");
}
}
}Output
Enter input string: This is a 5363 test string Match found
Updated on: 19-Nov-2019
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