Java String Buffer - how to delete

Question

I need to create a method which takes in a String and produces a new word which does not include vowels and replaces each consonant with its position in the original word. The word I am using is "program" so I should get back "12o457".

Below is my code - I am getting an out of bounds when I try to use the deleteCharAt but I can use append here fine.

public class Methods {

    public String getWord(String word){
        StringBuffer sb = new StringBuffer();


        for(int i=0; i<word.length(); i++)
        {
            if(word.charAt(i) =='a' ||
                word.charAt(i) == 'e' ||
                word.charAt(i) == 'i')
                {
                sb.deleteCharAt(i);
                }
        else if(word.charAt(i)=='o' || word.charAt(i)=='u')
            {
            sb.append(word.charAt(i));
            }
        else{sb.append((i));}
        }

        return sb.toString();

    }
}

It shouldn't contain vowels but you keep the `o` so, I don't understand it — Frakcool, Dec 29 '15 at 20:23
@Tunaki actually it should be `"01346"` (as far as I can see) — Frakcool, Dec 29 '15 at 20:25
You're trying to delete letters that you haven't added yet. Why? Just don't append them if you don't want them. — azurefrog, Dec 29 '15 at 20:26
Please don't use StringBuffer, it was replaced by StringBuilder more than 10 years ago. — Peter Lawrey, Dec 29 '15 at 20:42

score 1 · Answer 1 · answered Dec 29 '15 at 20:27

Well, you don't to need use method deleteCharAt(i) for StringBuilder, because it is empty by default and you add only characters you want and also in Strings indexes starts from 0, so you need append (i+1) for consonant's position

public static String getWord(String word) {
    StringBuilder sb = new StringBuilder();

    for (int i = 0; i < word.length(); i++) {

        if (word.charAt(i) == 'o' || word.charAt(i) == 'u') {
            sb.append(word.charAt(i));
        } else if (!(word.charAt(i) == 'a' ||
                word.charAt(i) == 'e' ||
                word.charAt(i) == 'i')) {
            sb.append((i + 1));
        }
    }

    return sb.toString();
}

score 1 · Accepted Answer · edited May 23 '17 at 11:59

You were trying to delete a char you never had on your StringBuilder, you just need to change your method as follows:

public String getWord(String word) {
    StringBuffer sb = new StringBuffer();
    for (int i = 0; i < word.length(); i++) {
        if (word.charAt(i) == 'o' || word.charAt(i) == 'u') {
            sb.append(word.charAt(i));
        } else if (word.charAt(i) != 'a' && word.charAt(i) != 'e' && word.charAt(i) != 'i') {
            sb.append((i + 1));
        }
    }
    return sb.toString();
}

This way you only add the letters you want for example o and u and skip a, e, i vowels and all consonants. Also, indexes in Java start from 0 so, to get your desired ouput, you needed to append i + 1 instead of just i.

After running the above code I get:

12o457

as expected. However you should rephrase your question because you don't want any vowel and you're adding o and u which are vowels. And you want the original position, so it's not i + 1 but i and it would give you:

01o346

However with a larger word this could give something like the following:

Input: programprogram
Output: 12o45789o111214

As you can see it becomes messy. Hopefully you won't use a word with a length > 10 chars.

Edit

Also I hadn't noticed this but as @PeterLawrey said in his comment above, don't use String Buffer instead use a String Builder. For more information about this, see StringBuilder vs StringBuffer

Thank you so much for your reply, works perfectly, sorry about the phrasing of the question I think I was looking at it for so long I lost the plot a bit! So simple now I see it, thanks again :) — jlog, Dec 29 '15 at 23:44

score 0 · Answer 3 · answered Dec 29 '15 at 20:35

0

    String string="how are you?";       
    string.replaceall("[a|e|o|i|u]","*");

    while(string.contains("*")){
    string.replaceFirst("*",string.indexOf("*")+1);
    }

this will work :)

answered Dec 29 '15 at 20:35

Mohammad Salem

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Java String Buffer - how to delete

3 Answers3