为什么 QXmlQuery 似乎在结果中添加了一个 `\n`?(以及如何解决?) [英] Why QXmlQuery seem to add a ` \n` to results? (and how to solve it?)

问题描述

写一点代码从XML中提取一些值，XPath的结果似乎在内容后面添加了\n.

Writing a little code to extract some values from an XML, the result of the XPath seem to add \n after the content.

#include <QCoreApplication>
#include <QXmlQuery>
#include <QString>
#include <QDebug>

auto main(int argn, char* argc[])->int
{
    QCoreApplication app(argn, argc);

    QString replyContent="<Root isOk='ok'/>";

    QXmlQuery query;
    query.setFocus(replyContent);
    query.setQuery("string(//@isOk)");

    // Attribute seem to add \n
    QString queryResult;    
    if (query.evaluateTo(&queryResult))
    {
        qDebug() << queryResult;              // Where this \n come from?
        qDebug() << queryResult.size();       // Why 3? shouldn't be 2?
    }
}

预期结果:

好的"
2

给定结果:

好的\n"
3

这显然有一些我想避免的副作用.

This obviously has some side effects which I would like to avoid.

为什么要添加这个\n?以及如何解决?

Why is this \n added? And how to solve it?

推荐答案

我认为这是由 QXmlFormatter 引入的，它用于将结果序列化为 <代码>QString;我怀疑 QXmlFormatter::endDocument 写了一个换行符.

I think that this is introduced by the QXmlFormatter that is used when serialising the results to a QString; I suspect that QXmlFormatter::endDocument writes a newline.

一种解决方法是输出到字符串列表，然后选择第一个元素:

One workaround would be to output to a string list instead, then pick the first element:

QStringList results;
if (query.evaluateTo(&results))
{
    const QString& queryResult = results.first();
    qDebug() << queryResult;
    qDebug() << queryResult.size();
}

如果您需要所有结果，您可以选择 join() 代替.

You might choose to join() the results instead, if you need them all.

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