Problems to convert a QString to QDateTime

Question

i have a problem to convert a QString to a QDataTime-Object.

The String looks like: "2008:09:23 14:18:03 and have a length of 20. The Problem is, if i remove the first character the output looks like: "008:09:23 14:18:03.

That's wrong with it? Can i delete all characters without the numbers?

The code:

        QDateTime date;
        QString d=QString::fromStdString(result.val_string);
        date.fromString(d,"yyyy:MM:dd hh:mm:ss");
        qDebug()<<d;
        qDebug()<<d.length()<<date.toString();

And the output:

 "008:09:23 14:18:03
 19 ""

Greetings

if i use date.fromString(d,"\"yyyy:MM:dd hh:mm:ss"); the result is the same. — 501 - not implemented, Sep 24 '13 at 17:40
Oh, I see, you have a doublequote at the beginning of the string. Can you show us how you removed the first character from `result.val_string`? — Nemanja Boric, Sep 24 '13 at 17:43
i tested also d.replace("\"","");...but the " is still at the output — 501 - not implemented, Sep 24 '13 at 17:50

Nemanja Boric · Accepted Answer · 2013-09-24T18:10:06.673

The double quotes are printed by the qDebug, they are not included in the QString itself. However, it seems that you have some non-printable character at the end of the original string which deletes the closing " sign. Try to copy only first 19 characters into the QString:

    QString d = QString::fromStdString(result.val_string.substr(0, 19));
    date.fromString(d,"yyyy:MM:dd hh:mm:ss");
    qDebug()<<d;
    qDebug()<<d.length()<<date.toString();

EDIT QDateTime.fromString is the static method returning the QDateTime object - it will not modify the object itself!

QDateTime date;
std::string val_string = "2008:09:23 14:18:03";
QString d = QString::fromStdString(val_string.substr(0, 19));
date = QDateTime::fromString(d,"yyyy:MM:dd HH:mm:ss");
qDebug()<<d;
qDebug()<<d.length()<<date.toString();

I tested this. But the result is the same. The Output looks like `"2008:09:23 14:18:03" ` but it doesn't recognize the date — 501 - not implemented, Sep 24 '13 at 18:01

score 0 · Answer 2 · answered Sep 24 '13 at 17:51

Use qPrintable(string); and it will get rid of the double quotes.

It isn't a problem with how the date makes the string. Its how qDebug handles strings. A char * is different from a QString according to QDebug.

http://qt-project.org/doc/qt-5.0/qtcore/qtglobal.html#qPrintable

http://qt-project.org/doc/qt-5.0/qtcore/qstring.html#toLocal8Bit

http://qt-project.org/doc/qt-5.0/qtcore/qbytearray.html#constData

Hope that helps.

Problems to convert a QString to QDateTime

2 Answers2