How can i remove a value from a qlist?

kanakas

Hi,

How can i remove a value from a QList< QMap<QString,QString> > test;?

i tried this : @test.removeOne(label);@ but i get an error

otherwise, how can i get the position of it to remove it?

label is a qstring.

koahnig

Since your value of QList is of type QMap < QString, QString > you need to use such a type for using "removeOne()":http://developer.qt.nokia.com/doc/qt-4.8/qlist.html#removeOne .
So it is probably more convenient for you to use "removeAt()":http://developer.qt.nokia.com/doc/qt-4.8/qlist.html#removeAt

kanakas

I also tried this:

@test.removeOne("test_id",label_cbx);@

but i always get an error (no matching function)!!

goetz

Why should it match? You give two arguments to a method that takes one... That should make you wonder firsthand...

To remove an entry from a QList< QMap<QString,QString> >, that is a list of maps, you must construct a map or use a reference found elsewhere that denotes the map to remove from the list.

stima_ua

hm...what are you want to do with QList<QMap<QString, QString>>? Mb I can told you better idea.

koahnig

As Volker already lined out.
However, I think this question is related to "your other post ":http://developer.qt.nokia.com/forums/viewthread/13330/ If this is really the case you are in a dead end anyhow.
To delete anything in your QList of QMaps with removeOne will be a bit painful, if you are not referencing.

stima_ua

about delete you want to delete all map that contains key? or just key from map?

kanakas

stima_ua, I want to remove a specific key of the map.

kanakas

I would appreciate it if sb writes a small example to understand it better

stima_ua

@
#include <QMap>
#include <QList>

#include <QDebug>

typedef QMap<QString, QString> Map;

void removeKey(QList<Map>& list, const QString& key)
{
int ret = 0;
QList<Map>::iterator i;
for ( i = list.begin(); i != list.end() && !ret; i++ )
{
ret = (*i).remove(key); // but only find first
}
}

int main()
{
QList<Map> list;

Map aMap;
Map bMap;

aMap["aKey1"] = "aValue1";
aMap["aKey2"] = "aValue2";

bMap["bKey1"] = "bValue1";
bMap["bKey2"] = "bValue2";

list.append(aMap);
list.append(bMap);

qDebug() << list;

removeKey(list, "aKey1");

qDebug() << list;

return 0;

}
@