You can match the non-white space characters using the meta character "\S".Exampleimport 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 = "\S";       //Compiling the regular expression       Pattern pattern = Pattern.compile(regex);       //Retrieving the matcher object       Matcher matcher = pattern.matcher(input);       int count = 0;     ... Read More

The metacharacter "\s" matches the white space characters in the given string.Example 1import 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 = "\s";       //Compiling the regular expression       Pattern pattern = Pattern.compile(regex);       //Retrieving the matcher object       Matcher matcher = pattern.matcher(input);       int count = 0;   ... Read More

All the characters other than the English alphabet (both cases) and, digits (0 to 9) are considered as non-word characters. You can match them using the meta character “\W”.Example 1import 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 = "^\W{5}";       //Compiling the regular expression       Pattern pattern = Pattern.compile(regex);       //Retrieving the ... Read More

The English alphabet (both cases) and, digits (0 to 9) are considered as word characters. You can match them using the meta character “\w”.Example 1import 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 = "^\w{5}";       //Compiling the regular expression       Pattern pattern = Pattern.compile(regex);       //Retrieving the matcher object       ... Read More

Using the or logical operator | of Java regular expressions you can match either of two given expressions.For example, if you need your regular expression should match more than one expression you can do so by separating the required expressions by “|”.Example 1import 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();       //Regular expression to match string that starts with hello or ... Read More

The greedy quantifiers provided by Java allows you to match the multiple occurrences of an expression. Where, Exp{n} impels the occurrence of the expression exp exactly n times.Exp{n, } impels the occurrence of the expression exp at least n times.Exp{n, m} impels occurrence of the expression exp at least n and utmost m times.Example 1import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample {    public static void main( String args[] ) {       //regular expression to accept 5 letter word       String regex = "\w{5}";       Scanner sc = new Scanner(System.in);     ... Read More

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 1import 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 ... Read More

The meta character “$” matches the end of a particular string i.e. it matches the last character of the string. For example, The expression “\d$” matches the string/line ending with a digit.The expression “[a-z]$” matches the string/line ending with a lower case alphabet.Example 1import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example {    public static void main(String args[]) {       //Reading String from user       System.out.println("Enter a String");       Scanner sc = new Scanner(System.in);       String input = sc.nextLine();       String regex = ".*[^a-zA-Z0-9//s]$";       //Compiling the ... Read More

To match a range of characters i.e. to match all the characters between two specified characters in a sequence you can use the character class as [a-z]The expression “[a-zA-Z]” accepts any English alphabet.The expression “[0-9&&[^35]]” accepts numbers except 3 and 5.Example 1import 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]*$";       //Compiling the regular expression   ... Read More

The character classes allow you to accept a single character from a fixed set of characters. For example, The expression “[tmp]” matches the characters t or, m or, p.The expression “[^tp]” matches the characters other than t or, p.Example 1import 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();       //Regular expression to match the characters t or, m or, p     ... Read More