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'.' selector'.' selector is a class level selector. The dot operator is used to create a style class which can then be applied on multiple html elements.'#' selector'#' selector is an element level selector. Hash operator is used to applying style on a particular element whose id is the same as used in '#' selectorExampleFollowing the example, shows usage of '.' as well as '#' selector on three div elements. Selector Example>/title> .blackBorder { border: 2px solid black; } #redDiv { ... 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
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
There are 7 common non printable characters used in general and each character has its own hexadecimal representation.NamecharactersHexa-decimal representationbell\a0x07Escape\e0x1BForm feed\f0x0CLine feed0x0ACarriage return\r0X0DHorizontal tab\t0X09Vertical tab\v0X0BExample 1 Live DemoFollowing Java program accepts an input text and counts the number of tab spaces in it −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(); String regex = "\t"; //Creating a pattern object Pattern pattern = ... Read More
The Possessive Quantifier [X?+] matches the X present once or not present at all.Example Live Demopackage com.tutorialspoint; import java.util.regex.Matcher; import java.util.regex.Pattern; public class PossesiveQuantifierDemo { private static final String REGEX = "T?+"; private static final String INPUT = "abcdTatW"; public static void main(String[] args) { // create a pattern Pattern pattern = Pattern.compile(REGEX); // get a matcher object Matcher matcher = pattern.matcher(INPUT); while(matcher.find()) { //Prints the start index of the match. System.out.println("Match String start(): "+matcher.start()); ... Read More
You can treat multiple characters as a single unit by capturing them as groups. You just need to place these characters inside a set of parentheses.You can count the number of groups in the current match using the groupCount() method of the Matcher class. This method calculates the number of capturing groups in the current match and returns it.Example Live Demoimport java.util.regex.Matcher; import java.util.regex.Pattern; public class Test { public static void main(String[] args) { String str1 = "This is an example HTML script where ever alternative word is bold."; //Regular expression to match contents ... Read More
Greedy quantifiers are the default quantifiers. A greedy quantifier matches as much as possible from the input string (longest match possible) if match not occurred it leaves the last character and matches again.Whereas a reluctant or, non-greedy quantifier matches as little as possible, initially the non-greedy quantifier matches the first character if match not occurred it adds another character from the input string and tries to match.If you place a "?" after a greedy quantifier it becomes reluctant or non-greedy quantifier. Following is the list of reluctant quantifiers −QuantifierDescriptionre*?Matches zero or more occurrences.re??Matches zero or, 1 occurrence.re+?Matches one or more ... Read More
Greedy quantifiers are the default quantifiers. A greedy quantifier matches as much as possible from the input string (longest match possible) if match not occurred it leaves the last character and matches again.A possessive quantifier is similar to a greedy quantifier the only difference is it tries to match as many character as it can initially and, if match not occurred unlike greedy quantifier it does not backtrack.If you place a "+" after a greedy quantifier it becomes possessive quantifier. Following is the list of possessive quantifiers −QuantifierDescriptionre*+Matches zero or more occurrences.re?+Matches zero or, 1 occurrence.re++Matches one or more occurrences.re{n}+Matches ... Read More
The regular expression "(?digit(?!\d)" matches the digit specified.The replaceAll() method accepts two strings: a regular expression pattern and, the replacement string and replaces the pattern with the specified string.Therefore, to remove all numbers in a string except 1 and 2, replace the regular expressions 1 and 2 with one and two respectively and replace all the other digits with an empty string.Example Live Demoimport java.util.Scanner; public class RegexExample { public static void main(String args[]) { //Reading String from user System.out.println("Enter a String"); Scanner sc = new Scanner(System.in); String ... Read More