Can't get QMap value using a <double> key

[Atr0p0s]

I'm facing the problem that I can't get the value of a QMap using a key other than using a QMapIterator key.

I have such QMap:
QMap<double, QList<double> > dynamic_Data;

And as you can see I can't get value using 133040 as a key.

QMapIterator<double, QList<double> > i(dynamic_Data);
if (i.hasNext()) {
    i.next();
    qDebug() << i.key() << ":" << i.value();
    qDebug() << dynamic_Data.value(i.key());
    qDebug() << dynamic_Data.value(double(133040));
}

Output:

133040 : (31.8689, 49.2064)
(31.8689, 49.2064)
()

Maybe I don't know something about QMap or I'm doing something wrong?

[JonB]

@Atr0p0s
How do you know that i.key() == double(133040)? Please print out the value of that expression. qDebug() << i.key() => 133040 is not necessarily accurate enough to tell you.

[Paul Colby]

I'm guessing that @JonB is correct.

You can also try:

qDebug() << Qt::fixed << qSetRealNumberPrecision(20) << i.key();

Cheers.

[Atr0p0s]

@Paul-Colby @JonB you are right, the key isn't exactly 133040. I guess it's better not to use double type for keys. Thank you, men.

[JonB]

@Atr0p0s said in Can't get QMap value using a <double> key:

I guess it's better not to use double type for keys

:) You have to be careful with doubles. As a great author once said [paraphrased]: "All [well, some] doubles are equal, and some doubles are more equal than others" ;-)