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Regular Expression "^" (caret) Metacharacter in Java
The subexpression/metacharacter “^” matches the beginning of a line. If you use this in a regular expression, it matches the sentence succeeding it in the input string.
Example 1
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class RegexExample {
public static void main( String args[] ) {
String regex = "^Hi how are you";
String input = "Hi how are you 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: 1
Example 2
The following Java program accepts 5 strings from the user and prints the strings starting with a digit.
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class StartingwithDigit {
public static void main( String args[] ) {
String regex = "^[0-9].*$";
Scanner sc = new Scanner(System.in);
System.out.println("Enter 5 input strings: ");
String input[] = new String[5]; Regular expressions - Answers
for (int i=0; i<5; i++) {
input[i] = sc.nextLine();
}
//Creating a Pattern object
Pattern p = Pattern.compile(regex);
System.out.println("Strings starting with digits: ");
for(int i=0; i<5;i++) {
//Creating a Matcher object
Matcher m = p.matcher(input[i]);
if(m.matches()) {
System.out.println(m.group());
}
}
}
}Output
Enter 5 input strings: sample string 1 sample string 2 11 sample string 3 22 sample string 4 43534 56353 636 Strings starting with digits: 11 sample string 3 22 sample string 4 43534 56353 636
Updated on: 18-Nov-2019
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