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Regular Expression re{ n} Metacharacter in Java
The subexpression/metacharacter “re{ n}” matches exactly n number of occurrences of the preceding expression.
Example 1
import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample { public static void main( String args[] ) { String regex = "to{1}"; String input = "Welcome to Tutorialspoint"; Pattern p = Pattern.compile(regex); Matcher m = p.matcher(input); int count = 0; while(m.find()) { count++; } System.out.println("Number of matches: "+count); } }
Output
Number of matches: 2
Example 2
Following Java program reads age value from the user it only allows a two-digit number.
import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample { public static void main( String args[] ) { String regex = "\d{2}"; System.out.println("Enter your age:"); Scanner sc = new Scanner(System.in); String input = sc.nextLine(); Pattern p = Pattern.compile(regex); Matcher m = p.matcher(input); if(m.matches()) { System.out.println("Age value accepted"); } else { System.out.println("Age value not accepted"); } } }
Output 1
Enter your age: 25 Age value accepted
Output 2
Enter your age: 2252 Age value not accepted
Output 3
Enter your age: twenty Age value not accepted
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