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Hi there, Where's my code wrong? It didn't pass validation. btw. I was looking for the appropriate REGEX for this taks with the following conditions: * 1 dollar must be replaced by one dollar * dollar 1 must be replaced by dollar one * 1dollar must not be replaced * dollar1 must not be replaced I worked with the INTERNET page" https://regex101.com/" to see if my REGEX ("[^a-z^A-Z]\d+) worked and it did, In fact I copy the proposed code(*) by regex101 :to my IntelIiJ IDEA and it worked as expected however the same REGEX in the code of this task failed.???? (*)

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Example {
    public static void main(String[] args) {
        final String regex = "[^A-Z^a-z]\\d+";
        final String string = "This costs 1 dollar, but this is 12.\n"
	 + "The variable is called file1.\n"
	 + "110 is a number.\n"
	 + "1 dollar is the cost of 1 pigrim";

        final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE);
        final Matcher matcher = pattern.matcher(string);

        while (matcher.find()) {
            System.out.println("Full match: " + matcher.group(0));

            for (int i = 1; i <= matcher.groupCount(); i++) {
                System.out.println("Group " + i + ": " + matcher.group(i));
            }
        }
    }
}

Surfing through the help I saw this new REGEX ("\\b\\d+\\b"), I checked it and it seems to be working but my code again didn't pass validation. Thanks

1. In a static block, initialize map with (number, word) pairs from 0 to 12 inclusive.
For example, (0, "zero"), (1, "one"), (2, "two")
2. Read the file name from the console, and then read the contents of the file.
3. Use map to replace all of the numbers with words.
4. Display the result.
5. Close the streams.

Example file data:
This costs 1 dollar, but this is 12. The variable is called file1. 110 is a number.

Example console output:
This costs one dollar, but this is twelve. The variable is called file1. 110 is a number.

Requirements:

The Solution class must have a public static Map<Integer, String> field called words that is initialized immediately.
The program must read the file name from the console (use BufferedReader).
The BufferedReader used for reading input from the console must be closed after use.
The program must read the file's contents (use FileReader).
The file input stream (FileReader) must be closed.
The program should write all of the lines from the file to the console, but any numbers must be replaced with the corresponding words in map.
The Solution class must have a static block that adds thirteen pairs to map.

package com.codegym.task.task19.task1924; import java.io.*; import java.util.HashMap; import java.util.Map; import java.util.regex.Matcher; import java.util.regex.Pattern; /* Replacing numbers */ public class Solution { public static Map<Integer, String> map = new HashMap<Integer, String>(); static{ map.put(0, "zero"); map.put(1, "one"); map.put(2, "two"); map.put(3, "three"); map.put(4, "four"); map.put(5, "five"); map.put(6, "six"); map.put(7, "seven"); map.put(8, "eight"); map.put(9, "nine"); map.put(10, "ten"); map.put(11, "eleven"); map.put(12, "twelve"); } public static void main(String[] args){ String fileName = null; // Getting the file name try(BufferedReader reader = new BufferedReader(new InputStreamReader(System.in))){ fileName = reader.readLine(); } catch (IOException e) { throw new RuntimeException(e); } try (BufferedReader fileReader = new BufferedReader(new FileReader(fileName))) { //final String REGEX ="[^A-Z^a-z]\\d+"; final String REGEX ="\\b\\d+\\b"; final Pattern pattern = Pattern.compile(REGEX); while(fileReader.ready()){ String line = fileReader.readLine().trim(); Matcher matcher = pattern.matcher(line); while(matcher.find()){ for(Map.Entry<Integer, String> pair : map.entrySet()){ if(Integer.parseInt(matcher.group(0).trim())==pair.getKey()) { line = line.replaceFirst(matcher.group(0).trim(), pair.getValue()); break; } } } System.out.println(line); } } catch (FileNotFoundException e) { throw new RuntimeException(e); } catch (IOException e) { throw new RuntimeException(e); } } }

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Lisa L

Level 47 , Nuremberg, Germany

22 April 2022, 11:46

This regex won't work properly ("[^A-Z^a-z]\\d+") it requires a not alnum as the first char and then grabs all following numbers. That leads to two problems. 12weeks shouldn't be replaced. But your regex matches it !1 should also not be a match but your regex does match it. The other regex using word borders however looks perfect. Then... if you use pattern-matcher, why not use it fully? Like the method reset... when using it you create one Matcher object outside the fileReader while loop. Then you just reset that matcher to the current line matcher.reset(line) where you now create a new Matcher object in each iteration. Next, if you find a match you parse for the number like int currentNum = Integer.parseInt(matcher.group()); now matcher has a replace method

matcher.appendReplacement(sbuf, map.containsKey(currentNum) ? map.get(currentNum) : matcher.group());

for that you need to define a StringBuffer- or Builder sbuf before, The appendReplacement adds not to replace stuff to the buffer/ builder and then replaces your match with what you define in the argument. Cause not all matches should be replaced I use a ternary operator here... you also can call a method in here... this is pretty flexible. After the find loop you just append the remainder of the line and you can proceed to the next line

matcher.appendTail(sbuf).append(System.lineSeparator());

as easy as that. with the containsKey method we even got around a problem you introduced when comparing objects. It should be a problem here as Integer uses caching for small numbers but it is not really correct to use == for that. You should go for equals. I like pattern-matcher a lot but without, with just using replaceAll you could do the task in just 5 lines (the loop).

LuisRC

Level 39 , Gijón, Spain

22 April 2022, 17:41

Knowing that my code is not efficient at all to do this job and taking as REGEX the one using word borders, wouldn't it do the work for this task? I've just get my code validated with your suggestions which btw I have loved cause its logic to solve the task. I have to improve my skills to use REGEX patterns. Thanks

Lisa L

Level 47 , Nuremberg, Germany

22 April 2022, 19:11

Your code does not look bad at all. The problem making it not validate... I just can guess. If I should try making it work I first would replace == with equals in line 48. But as said this shouldn't give issues for small numbers like in this task. Then I'd remove trim in line 48, 49 as this is not necessary at all (the word borders regex won't match spaces) . And finally I'd remove the trim in line 44. That is my favourite as it is not asked to remove whitespace here. You just are supposed to replace 1 - 12 with one - twelve. Nothing more, nothing less.

LuisRC

Level 39 , Gijón, Spain

22 April 2022, 20:49

Thanks Lisa.