Java regular expression logical operators-javaTutorial-php.cn

Java regular expression logical operators

Java Regular expressions supports 3 logical operators they are −

XY: X followed by Y
X|Y: X or Y
(X): capturing group.

XY: X followed by Y

This simply matches two single consecutive characters.

Example

Live Demo

import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class Test { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("Enter input text: "); String input = sc.nextLine(); String regex = "am"; //Creating a pattern object Pattern pattern = Pattern.compile(regex); //Matching the compiled pattern in the String Matcher matcher = pattern.matcher(input); if (matcher.find()) { System.out.println("Match occurred"); } else { System.out.println("Match not occurred"); } } }

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The Chinese translation of Output 1

is:

Output 1

Enter input text: sample text Match occurred

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Output 2

Enter input text: hello how are you Match not occurred

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X|Y

This matches either of the two expressions/characters surrounding "|"

Example

Live Demo

import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample { public static void main( String args[] ) { String regex = "Hello|welcome"; String input = "Hello how are you welcome to Tutorialspoint"; Pattern pattern = Pattern.compile(regex); Matcher matcher = pattern.matcher(input); int count = 0; while(matcher.find()) { count++; } System.out.println("Number of matches: "+count); } }

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Output

Number of matches: 2

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(X): Capturing Group

Capturing groups allow you to treat multiple characters as a unit. You just put these characters in a pair of brackets.

Example

Real-time demonstration

import 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 text"); Scanner sc = new Scanner(System.in); String input = sc.nextLine(); String regex = "(.*)(\d+)(.*)"; //Create a Pattern object Pattern pattern = Pattern.compile(regex); //Now create matcher object. Matcher matcher = pattern.matcher(input); if (matcher.find( )) { System.out.println("Found value: " + matcher.group(0) ); System.out.println("Found value: " + matcher.group(1) ); System.out.println("Found value: " + matcher.group(2) ); System.out.println("Found value: " + matcher.group(3) ); } else { System.out.println("NO MATCH"); } } }

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Output

Enter input text sample data with 1234 (digits) in middle Found value: sample data with 1234 (digits) in middle Found value: sample data with 123 Found value: 4 Found value: (digits) in middle

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