The regular expression “[a-zA-Z]+” matches one or the English alphabet. Therefore, to extract each word in the given input string −Compile the above expression of the compile() method of the Pattern class.Get the Matcher object bypassing the required input string as a parameter to the matcher() method of the Pattern class.Finally, for each match get the matched characters by invoking the group() method.Exampleimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class EachWordExample {    public static void main(String[] args) {       Scanner sc = new Scanner(System.in);       System.out.println("Enter sample text: ");       String data = ... Read More

To verify whether a given input string is a valid e-mail id match it with the following is the regular expression to match an e-mail id −"^[a-zA-Z0-9+_.-]+@[a-zA-Z0-9.-]+$"Where, ^ matches the starting of the sentence.[a-zA-Z0-9+_.-] matches one character from the English alphabet (both cases), digits, "+", "_", "." and, "-" before the @ symbol.+ indicates the repetition of the above-mentioned set of characters one or more times.@ matches itself.[a-zA-Z0-9.-] matches one character from the English alphabet (both cases), digits, "." and "–" after the @ symbol.$ indicates the end of the sentence.Exampleimport java.util.Scanner; public class ValidatingEmail {    public static void ... Read More

You can match a valid mobile number using the following regular expression −"\d{10}"A valid mobile number generally have 10 digits (in India).The metacharacter "\d" matches the digits from 0 to 9.The quantifier ex{n} suggests the repetition of ex n times.Example 1import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class PhoneNumberExample {    public static void main(String[] args) {       Scanner sc = new Scanner(System.in);       System.out.println("Enter your name: ");       String name = sc.nextLine();       System.out.println("Enter your Phone number: ");       String phone = sc.next();       //Regular expression to ... Read More

Following is the regular expression to match alphabet in the given input −"^[a-zA-Z]*$"Where,^ matches the starting of the sentence.[a-zA-z] matches the lower case and upper case letters.* indicates the occurrence for zero or more times.& indicates the end of the line.Example 1import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class ContainsAlphabetExample {    public static void main(String[] args) {       Scanner sc = new Scanner(System.in);       String names[] = new String[5];       for(int i=0; i

The regular expression “\s” matches the spaces in a string. The replaceAll() method accepts a string and a regular expression replaces the matched characters with the given string. To remove all the white spaces from an input string, invoke the replaceAll() method on it bypassing the above mentioned regular expression and an empty string as inputs.Example 1public class RemovingWhiteSpaces {    public static void main( String args[] ) {       String input = "Hi welcome to tutorialspoint";       String regex = "\s";       String result = input.replaceAll(regex, "");       System.out.println("Result: "+result);   ... Read More

Any word that contains numbers and letters is known as alphanumeric. The following regular expression matches the combination of numbers and letters."^[a-zA-Z0-9]+$";The matches method of the String class accepts a regular expression (in the form of a String) and matches it with the current string in case the match this method returns true else it returns false.Therefore, to find whether a particular string contains alpha-numeric values −Get the string.Invoke the match method on it bypassing the above mentioned regular expression.Retrieve the result.Example 1import java.util.Scanner; public class AlphanumericString {    public static void main(String args[]) {       Scanner sc ... Read More

The simple character class “[ ]” matches all the specified characters in it. The following expression matches the characters except for xyz."[xyz]"Similarly, the following expression matches all the vowels in the given input string."([^aeiouAEIOU0-9\W]+)";Then you can remove the matched characters by replacing them with the empty string “”, using the replaceAll() method.Example 1public class RemovingVowels {    public static void main( String args[] ) {       String input = "Hi welcome to tutorialspoint";       String regex = "[aeiouAEIOU]";       String result = input.replaceAll(regex, "");       System.out.println("Result: "+result);    } }OutputResult: H wlcm ... Read More

The simple character class “[ ]” matches all the specified characters in it. The meta character ^ acts as negation within the above character class i.e. the following expression matches all the characters except b (including spaces and special characters)"[^b]"Similarly, the following expression matches all the consonants in the given input string."([^aeiouyAEIOUY0-9\W]+)";Then you can remove the matched characters by replacing them with the empty string “”, using the replaceAll() method.Example 1public class RemovingConstants {    public static void main( String args[] ) {       String input = "Hi welc#ome to t$utori$alspoint";       String regex = "([^aeiouAEIOU0-9\W]+)"; ... Read More

You can group all the required characters to match within the square braces “[ ]” i.e. The metacharacter/sub-expression “[ ]” matches all the specified characters. Therefore, to match all the letters specify the vowel letters within these as shown below −[aeiouAEIOU]Example 1import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class MatchVowels {    public static void main( String args[] ) {       String regex = "[aeiouAEIOU]";       System.out.println("Enter input string: ");       Scanner sc = new Scanner(System.in);       String input = sc.nextLine();       //Compiling the regular expression       Pattern.compile(regex); ... Read More

The subexpression “[ ]” matches all the characters specified in the braces. Therefore, to move all the upper case letters to the end of a string −Iterate through all the characters in the given string.Match all the upper case letters in the given string using the regular expression "[A-Z]".Concatenate the special characters and the remaining characters to two different strings.Finally, concatenate the special characters string to the other string.Example 1public class RemovingSpecialCharacters {    public static void main(String args[]) {       String input = "sample B text C with G upper case LM characters in between";     ... Read More