How to match beginning of a particular string/line using Java RegEx

The meta character “^” matches the beginning of a particular string i.e. it matches the first character of the string. For example,

• The expression “^\d” matches the string/line starting with a digit.

• The expression “^[a-z]” matches the string/line starting with a lower case alphabet.

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[]) {
      //Reading String from user
      System.out.println("Enter a String");
      Scanner sc = new Scanner(System.in);
      String input = sc.nextLine();
      String regex = "^[^a-zA-Z0-9//s].*";
      //Compiling the regular expression
      Pattern pattern = Pattern.compile(regex);
      //Retrieving the matcher object
      Matcher matcher = pattern.matcher(input);
      if(matcher.matches()) {
         System.out.println("Match occurred");
      } else { 
         System.out.println("Match not occurred");
      }
   }
}

Output

Enter a String
#starting with a special character
Match occurred

Example 2

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 = "\.$";
      Scanner sc = new Scanner(System.in);
      System.out.println("Enter 5 input strings: ");
      String input[] = new String[5];
      for (int i=0; i<5; i++) {
         input[i] = sc.nextLine();
      }
      //Creating a Pattern object
      Pattern p = Pattern.compile(regex);
      for(int i=0; i<5;i++) {
         //Creating a Matcher object
         Matcher m = p.matcher(input[i]);
         if(m.find()) {
            System.out.println("String "+i+" ends with '.'");
         }
      }
   }
}

Output

Enter 5 input strings:
hello how are you.
where do you live
what is your name.
welcome to tutorialspoint
The Biggest Online Tutorials Library.
String 0 ends with '.'
String 2 ends with '.'
String 4 ends with '.'

Example 3

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 = "^[A-Z]";
      Scanner sc = new Scanner(System.in);
      System.out.println("Enter 5 input strings: ");
      String input[] = new String[5];
      for (int i=0; i<5; i++) {
         input[i] = sc.nextLine();
      }
      //Creating a Pattern object
      Pattern p = Pattern.compile(regex);
      for(int i=0; i<5;i++) {
         //Creating a Matcher object
         Matcher m = p.matcher(input[i]);
         if(m.find()) {
            System.out.println("String "+i+" starts with a capital letter");
         }
      }
   }
}

Output

Enter 5 input strings:
Sample text1
sample text2
hello how are you
Welcome to tutorialspoint
Good morning
String 0 starts with a capital letter
String 3 starts with a capital letter
String 4 starts with a capital letter