Syntax error Replacing all the matched contents Java regular expressions

Replacing all the matched contents Java regular expressions

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 Demo

import 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 = "\t+";
      //Creating a pattern object
      Pattern pattern = Pattern.compile(regex);
      //Matching the compiled pattern in the String
      Matcher matcher = pattern.matcher(input);
      int count = 0;
      while (matcher.find()) {
         count++;
      }
      System.out.println("No.of matches: "+count);
      String result = matcher.replaceAll(" ");
      System.out.println("Result: "+result);
   }
}

Output

Enter input text:
sample text with tab spaces
No.of matches: 4
Result: sample text with tab spaces

In the same way you can replace the first match using the replaceFirst() method of the Matcher class.

Example 2

 Live Demo

import 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";
      //Creating a pattern object
      Pattern pattern = Pattern.compile(regex);
      //Matching the compiled pattern in the String
      Matcher matcher = pattern.matcher(input);
      int count = 0;
      while (matcher.find()) {
         count++;
      }
      System.out.println("No.of matches: "+count);
      String result = matcher.replaceFirst("#");
      System.out.println("Result: "+result);
   }
}

Output

Enter input text:
test data 1 2 3
No.of matches: 3
Result: test data # 2 3
Updated on: 2020-01-13T06:34:25+05:30

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