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  1. Prepare
  2. Regex
  3. Grouping and Capturing
  4. Capturing & Non-Capturing Groups
  5. Discussions

Capturing & Non-Capturing Groups

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66 Discussions

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  • david_carroll
     + 0 comments

    2 Valid Patterns

    The literal pattern is simply:

    \okokok\

    However, the description leaves a clue for using a non-capture group to help with this pattern.

    The non-capture group pattern is:

    \(?:ok){3}\

    Testing against 6 "ok" values

    When testing the string input okokokokokok against these 2 patterns, the same 2 matches are returned:

    Matches Returned:

     - matches\[0\] okokok
 - matches\[1\] okokok

    Regarding Issues with other Patterns

    I noticed a few submissions that return true on matches, but they either produce the wrong number of matches or invalid match values.

    Invalid Pattern Returns 4 Matches instead of 2:

    \(ok){3}\

    Matches Returned:

     - matches\[0\] okokok
 - matches\[1\] ok
 - matches\[2\] okokok
 - matches\[3\] ok

    Invalid Pattern Returns wrong values:

    \(ok){3,}\

    Matches Returned:

     - matches\[0\] okokokokokok
 - matches\[1\] ok

  • arohi_agrawal111
     + 0 comments
    Regex_Pattern = r'(ok){3,}'

import re

print(str(bool(re.search(Regex_Pattern, input()))).lower())

  • trupti29
     + 0 comments

    Regex_Pattern = r'(ok){3,}' # Do not delete 'r'.

  • preethiannjacob
     + 0 comments

    Java 15:

    import java.io.*;
import java.util.*;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
public class Solution {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        // Pattern pattern = Pattern.compile("(ok){3,}");   //WORKS
        Pattern pattern = Pattern.compile("(ok)\\1\\1");    
        // \\1 means anything in first captured-group. Here ok is in first ()
        Matcher matcher = pattern.matcher(scanner.nextLine());
        System.out.println(matcher.find()); 
    }
}

  • Bavly_Zaher
     + 0 comments
    (ok){3,}