StringBuilder remove comma at the end of Last record

Question

I am using StringBuilder to show comma between records, but also getting comma at the end of Last Record

How to control on this ? I don't like to see comma at the end of last record - because it's useless

   for (int i = 0; i < arrayList.size(); i++) {

        String name = arrayList.get(i).getName();
        int price = arrayList.get(i).getPrice();

        stringBuilder.append(strName);
        stringBuilder.append(" - "+price+",");

    }

        stringFinal = stringBuilder.toString();

Either subString the String returned or call `deleteCharAt(...)` passing in StringBuilder length - 1. — Hovercraft Full Of Eels, Aug 20 '15 at 11:34
Consider [`String::join`](https://docs.oracle.com/javase/8/docs/api/java/lang/String.html#join-java.lang.CharSequence-java.lang.Iterable-) — khelwood, Aug 20 '15 at 11:38
Any specific reason you want to remove it after adding? Why not prevent it being added for the last item itself? — Mohit Kanwar, Aug 20 '15 at 11:42

Fred Porciúncula · Answer 1 · 2015-08-20T12:47:44.780

Java 8 Solution

You don't need any check when using Java 8. All you need is to use StringJoiner (or String.join()).

StringJoiner joiner = new StringJoiner(",");
for (int i = 0; i < arrayList.size(); i++) {
    String name = arrayList.get(i).getName();
    int price = arrayList.get(i).getPrice();

    joiner.add(strName + " - " + price);
}
String joinedString = joiner.toString();

And you can make it even cleaner by taking advantage of the Stream API (thanks to @Sasha):

String joinedString = String.join(",", list.stream().map(
        e -> e.getName() + " - " + e.getPrice()).collect(Collectors.toList()));

score 4 · Accepted Answer · answered Aug 20 '15 at 11:35

Add a check for the last item.

if (i < arrayList.size() - 1) {
  stringBuilder.append(" - "+price+",");
} else {
  stringBuilder.append(" - "+price);
}

or:

stringBuilder.append(" - "+price);
if (i < arrayList.size() - 1) {
  stringBuilder.append(",");
}

score 2 · Answer 3 · answered Aug 20 '15 at 11:54

2

You can just delete the last character:

 stringBuilder.deleteCharAt(stringBuilder.length()-1);
 stringFinal = stringBuilder.toString();

that would be the simplest solution.

answered Aug 20 '15 at 11:54

Tawcharowsky

615
4
18

score 1 · Answer 4 · answered Aug 20 '15 at 11:59

1

int index = stringBuilder.lastIndexOf(",");
if (index != -1){
    stringBuilder.replace(index, index+1, "");
}
String stringFinal = stringBuilder.toString();

answered Aug 20 '15 at 11:59

Casper

216
2
7

score 0 · Answer 5 · answered Aug 20 '15 at 11:39

Or loop till size - 1 and then add the last element after wards without a comma.

int i = 0, price = 0;
String name = null;
for (i = 0; i < arrayList.size() - 1; i++) {
 name = arrayList.get(i).getName();
 price = arrayList.get(i).getPrice();

 stringBuilder.append(strName);
 stringBuilder.append(" - "+price+",");
}

name = arrayList.get(i).getName();
price = arrayList.get(i).getPrice();
stringBuilder.append(strName);
stringBuilder.append(" - "+price);
stringFinal = stringBuilder.toString();

score 0 · Answer 6 · answered Aug 20 '15 at 11:39

    for (int i = 0; i < arrayList.size(); i++) {

    String name = arrayList.get(i).getName();
    int price = arrayList.get(i).getPrice();

    stringBuilder.append(strName);
    if(i== arrayList.size()-1)
       stringBuilder.append(" - "+price);
    else
    stringBuilder.append(" - "+price+",");

     }

    stringFinal = stringBuilder.toString();

score 0 · Answer 7 · answered Aug 20 '15 at 11:51

Instead of placing it in last you can write it in front like :-

        String name = arrayList.get(0).getName();
        int price = arrayList.get(0).getPrice();

        stringBuilder.append(strName).append(" - "+price);
for (int i = 1; i < arrayList.size(); i++) {

        name = arrayList.get(i).getName();
        price = arrayList.get(i).getPrice();

        stringBuilder.append(","+strName).append(" - "+price);

    }

        stringFinal = stringBuilder.toString();

StringBuilder remove comma at the end of Last record

7 Answers7

Java 8 Solution