QHash in QList in QHash

xiit

Basically I was wondering if it is possible to put a QHash in a QList which I then put in a QHash.

This is my code:

@ QHash<QString, QVariant> info;

info.insert("someinfo", "blah blah");
info.insert("moreinfo", 123456);

QList<QHash<QString, QVariant> > list;

QHash<QString, QVariant> blah;

blah.insert("some", "stuff");

list << blah;

info.insert("somelist", list);@

But the last line (14) obviously gives me an error as I do not know the proper way to approach this.

@error: no matching function for call to 'QHash<QString, QVariant>::insert(const char [9], QList<QHash<QString, QVariant> >&)'

candidates are: QHash<Key, T>::iterator QHash<Key, T>::insert(const Key&, const T&) [with Key = QString, T = QVariant]@

Any ideas?

Thanks in advance.

Chris Kawa

Try this:
@
info.insert("somelist", QVariant::fromValue(list));
@

Sam

[quote author="Krzysztof Kawa" date="1358076526"]Try this:
@
info.insert("somelist", QVariant::fromValue(list));
@[/quote]

Tried but didnt work. I think we need to register using Q_DECLARE_METATYPE for the list but that too didn't work.

Chris Kawa

Just tried this and it prints "bar" as expected:
@
#include <QDebug>
#include <QList>
#include <QHash>
#include <QVariant>
#include <QString>

int main()
{
QHash<QString, QVariant> hash;
hash["foo"] = "bar";

QList<QHash<QString, QVariant> > list;
list << hash;

QHash<QString, QVariant> hash2;
hash2.insert("buzz", QVariant::fromValue(list));



QList<QHash<QString, QVariant> > bar;
bar = hash2["buzz"].value<QList<QHash<QString, QVariant> > >();

qDebug() << bar[0]["foo"].toString();

return 0;

}
@

utcenter

Or... be a man and use typedefs :P

Chris Kawa

[quote author="utcenter" date="1358092235"]Or... be a man and use typedefs :P [/quote]

Well sure, in a production code. But the point here was to show it actually works with those types, thus the overly verbose syntax.

utcenter

^^I didn't mean you but the OP, your example is perfectly adequate.

Even if for some reason it is necessary to put a hash in a list in a hash, doing so with the raw containers themselves is not something I would consider a good practice, it is much better to build up this kind of structure with typedefs, wrapper classes and accessor methods to make the whole process with working with this transparent.

xiit

Okay, now I've managed to store it with the following code:

@ QVariantHash info;

info.insert("someinfo", "blah blah");
info.insert("moreinfo", 123456);

//

QVariantList list;

QVariantHash blah;
blah.insert("some", "stuff");

list << blah;

info.insert("somelist", list);

//

QVariantHash myHash = info["somelist"].toList().at(0).toHash();

qDebug() << myHash["some"].toString(); // outputs "stuff"@

Is there any "nicer" way of doing this?

EDIT: I'm new to both C++ and Qt so I pretty much have no idea what I am doing, just playing around. :P