Gracefully remove "\n" delimiter after last String within StringBuilder

Question

Have following Java code,that creates StringBuilder with "\n",i.e. carriage return delimiters:

while (scanner.hasNextLine()){
    sb.append(scanner.nextLine()).append("\n");
}

It's occurred,that after last String(line) had "\n" symbol.

How to gracefully remove last "\n" from resulting StringBuilder object?

thanks.

Answer 1

This has always worked for me

sb.setLength(sb.length() - 1);

Operation is pretty lightweight, internal value holding current content size will just be decreased by 1.

Also, check length value before doing it if you think buffer may be empty.

Answer 2

if (scanner.hasNextLine()) 
  sb.append(scanner.nextLine());
while (scanner.hasNextLine()){
  sb.append("\n").append(scanner.nextLine());
}

Answer 3

If you're working with a small enough number of lines, you can put all the lines in a List<String> and then use StringUtils.join(myList, "\n");

Another option is to trim() the resulting string.

Answer 4

bool isFirst = true;
while (scanner.hasNextLine()){
  if(!isFirst)
    sb.append("\n"));
  else
    isFirst = false;

  sb.append(scanner.nextLine());

}

Answer 5

sb.deleteCharAt(sb.length()-1);

Answer 6

You could build the result without a newline to get rid of:

String separator = "";
while (scanner.hasNextLine()){
    sb.append(separator).append(scanner.nextLine());
    separator = "\n";
}

Answer 7

Instead of having to remove it you could simply never add it.

while (scanner.hasNextLine()) {
    if (sb.length()>0) sb.append("\n");
    sb.append(scanner.nextLine());
}