How do I remove trailing whitespace from a QString?

Question

I want to remove all the trailing whitespace characters in a QString. I am looking to do what the Python function str.rstrip() with a QString

Answer 1

No deep copy and no repeated calls to size/chop:

QString & rtrimInPlace (QString &str) {
    for (int n = str.size() - 1; n >= 0; -- n)
        if (!str.at(n).isSpace()) {
            str.truncate(n + 1);
            break;
        }
    return str;
}

Answer 2

QString has two methods related to trimming whitespace:

• QString QString::trimmed() const
  Returns a string that has whitespace removed from the start and the end.
• QString QString::simplified() const
  Returns a string that has whitespace removed from the start and the end, and that has each sequence of internal whitespace replaced with a single space.

If you want to remove only trailing whitespace, you need to implement that yourself. Here is such an implementation which mimics the implementation of trimmed:

QString rstrip(const QString& str) {
  int n = str.size() - 1;
  for (; n >= 0; --n) {
    if (!str.at(n).isSpace()) {
      return str.left(n + 1);
    }
  }
  return "";
}

Answer 3

QString::Trimmed() removes whitespace from the start and the end - if you are sure there is no whitespace at the start you can use this.