Thread: How to make regular expression allows spaces between words

Hi, I am learning how to use regex to split a word into syllables and then add a letter “p” and repetition after each syllable. If a syllable starts with a consonant(s), then the consonant(s) should be removed. In this case, the definition of syllable is zero or more consonants followed by a single vowel followed by zero or more consonants. For example, I have an input:

Two peas in a pod

The expected output:

Twopo pepeaspas inpin apa podpod

I have written this code, the only problem is that it does not allow spaces between words. May I ask suggestions to adjust the code? Thank you

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
// A syllable is defined as: zero or more consonants followed by a single vowel followed by zero or more consonants.
// In this case, only {aeiou} are considered vowels.
public class Language {
    public static void main(String[] args) {
        String input = "Two peas in a pod";
        String addP = "p";
        // Test whether the regular expression matches the pattern.
        Matcher m = Pattern.compile("([^aeiou]?[aeiou])((nghhgfdgy|[^aeiou])(?![aeiou]))?", Pattern.CASE_INSENSITIVE).matcher(input);
        int s = 0;
        // Find the next expression that matches the pattern.
        while (m.find()) {
            // If the first letter of syllable starts with a vowel, then add p before repetition
            if (input.charAt(m.start()) == 'a' || input.charAt(m.start()) == 'i' || input.charAt(m.start()) == 'o'
            || input.charAt(m.start()) == 'e' || input.charAt(m.start()) == 'u') {
                System.out.print(input.substring(s, m.end()).trim() + addP + input.substring(m.start(), m.end()).trim());
            }
            // If the first letter of syllable starts with a consonant, then add p before repetition and remove the first letter of repetition
            else {
                System.out.print(input.substring(s, m.end()).trim() + addP + input.substring(m.start(), m.end()).substring(1).trim());
            }
        s = m.end();
        }
    }
}

Output:

Twopopepeaspasinpinapapodpod

The code is missing the import statements that are required to compile it. Please post the necessary import statements.

Why aren't there any comments in the program that describe what it is supposed to do and what the rules are that it is trying to follow?
Does your instructor penalize you for adding comments to the code?
Personally I find it very useful when writing code like this that has to follow some rules that those rules are in the code as comments.

Ok, thank you.

Can you describe what is wrong with the current output? What needs to change for it to be correct?

Ok what needs to be changed to the print statement so that the desired spaces are printed?

I notice that there are no comments for the regular expression to explain what its different parts are supposed to do.

Does it mean that I need to change my print statement rather than changing the regular expression?

[^aeiou] = Match a single character not present in the list (a,e,i,o,u) - consonant(s)
[aeiou] = Match a single character present in the list (a,e,i,o,u) - vowel(s)
(nghhgfdgy|[^aeiou]) = Matches a single consonant or multiple consonants
(?![aeiou]) = Match a single character present in the list

I'm not any good with regular expressions. I never use them.

Where would be the best place to control when a space was printed? Can a regExp be made to match the desired space so it would be printed as part of the matched String?
Or can the print statement be changed to print the space where it is desired?

Why are there calls to the trim() method in the print statement? That would remove spaces from the String being printed.

Start with the first thing that is wrong in the output and work on changing the code to fix it. It is better when trying to correct code to minimize the problems and work on them one at a time instead of trying to fix them all at once.