Question

我想删除<条形码>QString中所有线索白空间特征。我期待着以<代码>QString的<<>str.rstrip(>。

I did some Googling, and found this: http://www.qtforum.org/article/20798/how-to-strip-trailing-whitespace-from-qstring.html

因此,我现在有权这样做:

while(str.endsWith(     )) str.chop(1);
while(str.endsWith(  
  )) str.chop(1);

是否有更简单的方法这样做? 我想从一开始就保留所有的白色空间。

Answer 1

<代码>QString有两个方法与三明白空间有关:

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.

如果你只想拆除破碎的白色空间,那么你需要执行这一天。此处是实施<代码>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 2

QString provides only two trimming-related functions. In case if they don t suit your needs, I m afraid you need to implement your own custom trimming function.

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.

QString str = "  lots	 of
whitespace
 ";
str = str.simplified();
// str == "lots of whitespace";

QString QString::trimmed () const
Returns a string that has whitespace removed from the start and the end.

QString str = "  lots	 of
whitespace
 ";
str = str.trimmed();
// str == "lots	 of
whitespace"

Answer 3

如果你在开始时没有或不需要任何白色空间,你可以使用QString QString:trimmed () const。

这忽略了任何内部白天空间,安德烈斯·西奈尼科夫提供了另一种解决办法加以纠正。

Answer 4

You can do it with a regexp:

#include <QtCore>

int main(int argc, char** argv)
{
    QCoreApplication app(argc, argv);

    QString str("Hello world    ");

    qDebug() << str;

    str.remove(QRegExp("\s+$"));

    qDebug() << str;

    return 0;
}

Whether this would be faster, I m not sure.

Answer 5

如果你不希望提供大体的复印件:

QString & rtrim( QString & str ) {
  while( str.size() > 0 && str.at( str.size() - 1 ).isSpace() )
    str.chop( 1 );
  return str;
}

Answer 6

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.

Answer 7

1. 没有深度拷贝,也没有一再要求大小/秒:

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 8

这是Frank S. Thomas的回答的一种变化:

QString rstrip(const QString& str, const char *skip = " 
	") {
  int n = str.size() - 1;
  for (; n >= 0; --n) {
    if (0 == strchr(skip, str.at(n).toAscii()))
      return str.left(n + 1);
  }
  return "";
}

Answer 9

如我所知,唯一正在运行的系统是trimmed(<>/code>和simplated(>)。因此,你将需要人工裁量。在这种情况下,您应使用<代码>QChar的功能isspace()来检查特性是否具有空间特性。

Answer 10

你们可以增加一个非空间的果园,然后拆除地皮。

str1=QString("-"+str).trimmed().mid(1);

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