I've a QMap object and I am trying to write its content to a file. QMap<QString, QString> extensions; //.. for(auto e : extensions) { fout << e.first << "," << e.second ...

I have a QMap consist of pointers to class objects, allocated using new. I need to delete all these pointers. What is the proper way of doing this with QMap ? I can do it this way: QList<ClassN...

I would like to use QMultiMap (which is derived from QMap) to store key/value pairs. Since I can have keys multiple times I would prefer to use QMultiMap. Assume I would insert the following pairs...

I am using Qt5 on Windows 7. In my current app, I have the following (simplified here): QMap<int, QString> map; int _WorkerThread_(int index) { QString new_element = "whatever"; ... ...

#include <QtCore/QCoreApplication> #include <QVariant> #include <QtDebug> int main(int argc, char *argv[]) { QCoreApplication a(argc, argv); QVariantMap map; map["foo"] = QVar...

Edit 7 : After quite a bit of help, I've been able to get a map that is getting close to the results I need. But I still need to have the state boundaries come through on the map, but I can't fig...

I need to know in QMap second value there is. Functions like first() and last() are useless. Do i have to use iterator, some kind of loop? QMap<int, QString> map; map.insert(1, "Mario"); ...

Generally speaking, what is the correct way to deep copy Qt containers? I'm not worried about deep copying the containers recursively, although addressing such would be helpful.

I often see code like: if(myQMap.contains("my key")){ myValue = myQMap["my key"]; } which theoretically performs two look-up's in the QMap. My first reaction is that it should be replaced by ...

I couldn't find a way to set a custom comparator function for QMap, like I can for std::map (the typename _Compare = std::less<_Key> part of its template arguments). Does QMap have a way to ...

I am trying to prevent naked pointers, to prevent memory leaking etc. I also want to map int to INuiSensor*. Since I am also using Qt I tried to use QMap<int, std::unique_ptr<INuiSensor>&g...

I wounder why does QMap realised over skiplist data-structure and not rb-tree? There is very interesting SO thread about concurrency data-structs and skip-list benefits over rb-tree, pros and cons....

How can I expose QMap from C++ to QML? Using QList I can use QDeclarativeListProperty.

I was wondering for how long the reference to a value inside a Qt container, especially a QHash or a QMap is valid. By valid I mean if it is guaranteed to still point to the correct location inside...

I am trying find nearest RGB value in QMap (I know it probably should be HSV, but that is not the problem). Here is what I got so far: it = images_map.find(current_rgb); if(it != images_map.beg...

What should i use between QMap::insertMulti and QMultiMap to handle : 2 -> abc 2 -> def 3 -> ghi 3 -> jkl What's the difference enter the 2 solutions ?

QVariant (needed for QSettings class) supports creation from QMap<QString, QVariant> But trying to initialise something like this: QMap<QString, QVariant(QMap<QString, QVariant>)&g...