The subexpression/metacharacter “\A” matches the beginning of the entire string.Example 1import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample {    public static void main( String args[] ) {       String regex = "\AHi";       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);    } }OutputNumber of matches: 1Example 2Following Java program accepts a ... Read More

The subexpression/metacharacter “\G” matches the point where the last match finished.Exampleimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample {    public static void main( String args[] ) {       String regex = "\G[0-9]";       Scanner sc = new Scanner(System.in);       System.out.println("Enter a string: ");       String input = sc.nextLine();       Pattern p = Pattern.compile(regex);       Matcher m = p.matcher(input);       int count = 0;       String digits = "";       System.out.println("Digits in the previous match:");       while(m.find()) {   ... Read More

The subexpression/metacharacter “\D” matches the non-digits.Example 1import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample {    public static void main( String args[] ) {       String regex = "\D";       String input = "This is sample text 12 24 56 89 24";       Pattern p = Pattern.compile(regex);       Matcher m = p.matcher(input);       int count = 0;       while(m.find()) {          count++;       }       System.out.println("Number of matches: "+count);    } }OutputNumber of matches: 24Example 2import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public ... Read More

The subexpression/metacharacter “\d” matches the digits.Example 1import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample {    public static void main( String args[] ) {       String regex = "\d 24";       String input = "This is sample text 12 24 56 89 24";       Pattern p = Pattern.compile(regex);       Matcher m = p.matcher(input);       int count = 0;       while(m.find()) {          count++;       }       System.out.println("Number of matches: "+count);    } }OutputNumber of matches: 2Example 2Following is a Java program that ... Read More

The subexpression/metacharacter “\S” matches the non-white space characters.Example 1import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample {    public static void main( String args[] ) {       String regex = "\S";       String input = "Hello 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);    } }OutputNumber of matches: 38Example 2import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; ... Read More

The subexpression/metacharacter “\s” matches the white space equivalent.Example 1import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample {    public static void main( String args[] ) {       String regex = "\s";       String input = "Hello 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);    } }OutputNumber of matches: 7Example 2The following example reads a string ... Read More

The subexpression/metacharacter “\W” matches the non-word characters.Example1import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample {    public static void main(String args[]) {       String regex = "\W!";       String input = "Hello 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);    } }OutputNumber of matches: 1Example2Following example reads 5 string values and prints those that contain ... Read More

The subexpression/metacharacter “\w” matches the word characters i.e. a to z and A to Z and 0 to 9.Example 1import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample {    public static void main( String args[] ) {       String regex = "\w to";       String input = "Hello 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);   ... Read More

The subexpression/metacharacter “[^...]” matches any single character, not in brackets.Example 1import java.util.regex.Matcher; import java.util.regex.Pattern; public class SpecifiedCharacters {    public static void main( String args[] ) {       String regex = "[^hwtyoupi]";       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);    } }OutputNumber of matches: 21Example 2The following Java program accepts ... Read More

The subexpression/metacharacter “re*” matches 0 or more occurrences of the preceding expression.Example 1import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample {    public static void main( String args[] ) {       String regex = "aabc*";       String input = "aabcabcaabcabbcaabcbcaabc";       Pattern p = Pattern.compile(regex);       Matcher m = p.matcher(input);       int count = 0;       while(m.find()) {          count++;       }       System.out.println("Number of matches: "+count);    } }OutputNumber of matches: 4Example 2import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class MatchAllCharacters ... Read More