Programming Articles - Page 2156 of 3366

Named capturing groups allows you to reference the groups by names. Java started supporting captured groups since SE7.Example Live Demoimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class ReplaceAll{    public static void main(String[] args) {       Scanner sc = new Scanner(System.in);       System.out.println("Enter input text: ");       String input = sc.nextLine();       String regex = "(?[\d]{2})-(?[\d]{5})-(?[\d]{6})";       //Creating a pattern object       Pattern pattern = Pattern.compile(regex);       //Matching the compiled pattern in the String       Matcher matcher = pattern.matcher(input);       while (matcher.find()) { ... Read More

'|' Bitwise OR operator'|' operator is a bitwise OR operator and is used to set the bit to 1 if any of the corresponding bit is 1.'||' Logical Or operator'||' is a logical Or operator and works on complete operands as whole.ExampleFollowing example, shows usage of '|' vs '||' operators. Live Demo    PHP Example     Output$x | $y = 3 $x || $y = 1

Once you compile the required regular expression and retrieved the matcher object by passing the input string as a parameter to the matcher() method.You can replace all the matched parts of the input string with another str4ing using the replaceAll() method of the Matcher class.This method accepts a string (replacement string) and replaces all the matches in the input string with it and returns the result.Example 1 Live Demoimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class ReplaceAll{    public static void main(String[] args) {       Scanner sc = new Scanner(System.in);       System.out.println("Enter input text: ");     ... Read More

To match a pattern within another match you need to compile the regular expression to match the outer pattern find the match retrieve the results and pass the results as input to the inner Matcher object.Example Live Demoimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class MatcherExample {    public static void main(String[] args) {       int start = 0, len = -1;       Scanner sc = new Scanner(System.in);       System.out.println("Enter input text: ");       String input = sc.nextLine();       String regexOuter = "(.*?)";       String regexInner = "\d+";   ... Read More

'!==' comparison operator'!==' operator checks the unequality of two objects with a type check. It does not converts the datatype and makes a typed check.For example 1 !== '1' will results true.'==!' comparison operator'==!' operator is combination of two operators and can be written as == (!operands).ExampleFollowing example, shows usage of '!==' vs '==!' operators. Live Demo    PHP Example     Output$x !== operator $y = bool(true) $x ==! operator $y = bool(true)

Java does not provide any method to retrieve the list of all matches we need to use Lists and add the results to it in the while loop.Example Live Demoimport java.util.ArrayList; import java.util.Iterator; import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class ListOfMatches{    public static void main(String[] args) {       Scanner sc = new Scanner(System.in);       System.out.println("Enter input text: ");       String input = sc.nextLine();       String regex = "\d+";       //Creating a pattern object       Pattern pattern = Pattern.compile(regex);       ArrayList list = new ArrayList();   ... Read More

The start() method of the java.util.regex.Matcher class returns the starting position of the match (if a match occurred).Similarly, the end() method of the Matcher class returns the ending position of the match.Therefore, return value of the start() method will be the starting position of the match and the difference between the return values of the end() and start() methods will be the length of the match.Example Live Demoimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class MatcherExample {    public static void main(String[] args) {       int start = 0, len = -1;       Scanner sc = new ... Read More

Using capturing groups you can treat multiple characters as a single unit. You just need to place the characters to be grouped inside a set of parentheses. For example −(.*)(\d+)(.*)If you are trying to match multiple groups the match results of each group is captured. You can get the results a group by passing its respective group number to the group() method. 1, 2, 3 etc.. (from right to left) group 0 indicates the whole match.Example Live Demoimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class CapturingGroups {    public static void main( String args[] ) {       System.out.println("Enter input ... Read More

The meta character "\b" matches word boundaries. i.e. it matches before the first and after the last word characters and between word and non-word characters.Therefore to match a whole word you need to surround it between the word boundary meta characters as −\btest\bExample Live DemoFollowing Java example counts and prints the number of occurrences of the word test in the given input string.import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample1 {    public static void main(String[] args) {       Scanner sc = new Scanner(System.in);       System.out.println("Enter input text: ");       String input = sc.nextLine(); ... Read More

The character classes in Java regular expression is defined using the square brackets "[ ]", the character class matches a single character from the specified or, set of possible characters.For example, the regular expression [abc] matches a single character a or, b or, c. Similarly, "[a-z]" matches a character from a to z.Example 1 Live Demoimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample1 {    public static void main(String[] args) {       Scanner sc = new Scanner(System.in);       System.out.println("Enter input text: ");       String input = sc.nextLine();       String regex = "[a-z]"; ... Read More