The cvtColor() method of the Imgproc class changes/converts the color of the image from one to another. This method accepts three parameters −src − A Matrix object representing source.dst − A Matrix object representing the destination.code − An integer value representing the color of the destination image.To convert a colored ... Read More

The imread() method of the Imgcodecs class accepts a string value representing a file name as a parameter. This method reads the contents of the specified file into a matrix object and returns it. Using this method you can read the contents of an image.In addition to this, the Imgcodecs class ... Read More

Using the OpenCV library you can perform image processing operations such as image filtering, geometrical image transformations, color space conversion, histograms, etc.Writing an imageWhenever you read the contents of an image using the imread() method of the Imgcodecs class the result is read into the Matrix object.You can write/save an ... Read More

The replaceAll() method of Collections interface accepts a List object, two typed parameters representing old and new values, replaces the old values with the new values in the list.Example Live Demoimport java.util.ArrayList; import java.util.Collections; import java.util.List; public class ReplaceAllExample {    public static void main(String args[]) {       List ... 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 ... Read More

Following regular expression accepts a string with parenthesis −"^.*[\(\)].*$";^ matches the starting of the sentence..* Matches zero or more (any) characters.[\(\)] matching parenthesis.$ indicates the end of the sentence.Example 1 Live Demoimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class SampleTest {    public static void main( String args[] ) {   ... Read More

The subexpression/metacharacter "\Q" escapes all characters up to "\E" i.e. you can escape metacharacters in the regular expressions by placing them in between \Q and \E. For example, the expression [aeiou] matches the strings with vowel letters in it.Example  Live Demoimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class SampleProgram {   ... Read More

This class matches all tabs or spaces.Example  Live Demoimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class PrintableCharacters {    public static void main(String args[]) {       //Reading String from user       System.out.println("Enter a string");       Scanner sc = new Scanner(System.in);       String input ... Read More

This class \p{InGreek} matches Greek characters.Example Live Demoimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example1 {    public static void main(String args[]) {       //Reading String from user       System.out.println("Enter a string");       Scanner sc = new Scanner(System.in);       String input = ... Read More

This class matches alpha numeric characters.Example  Live Demoimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class AlphanumericExample {    public static void main(String args[]) {       //Reading String from user       System.out.println("Enter a string");       Scanner sc = new Scanner(System.in);       String input = ... Read More