dynamic matrix of QStrings

Hi all;

I am tring to create a dynamic matrix of QString but I have not succed.

Are there any possibility to do it?

thanks

Show us what you tried.
Would that do?

Code:

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QVector<QVecotr<QString> > stringMatrix;

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What it is you need it for?
May be what you need is a map?

Code:

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QVector<QVecotr<QString> > stringMatrix;

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:rolleyes:

Code:

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QVector<QVector<QString> > stringMatrix;

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And.... what is the problem?

Code:

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template <class type>
class Q2DVector : public QVector< QVector<type> >
{
	public:
		Q2DVector() : QVector< QVector<type> >(){};
		Q2DVector(int rows, int columns) : QVector< QVector<type> >(rows) {
			for(int r=0; r<rows; r++) {
				this[r].resize(columns);
			}
		};
		virtual ~Q2DVector() {};
};
typedef Q2DVector<QString> Q2DQStringVector;

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I am now even able to do:

Code:

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Q2DQStringVector my2DArray(4,10);
	my2DArray[1][5] = "thanks Robin Ericsson schrieb from qt-interest";

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:rolleyes:

Quote:

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Originally Posted by high_flyer

And.... what is the problem?

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How can I (Read/Write) (from/to) element (i,j) according to your solution?

Quote:

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Originally Posted by QiT

How can I acced to element (i,j) according to your solution?

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In exactly the same way. The spoon-fed Q2DQStringVector is just a template wrapper around the same underlying data structure suggested by high_flyer with the only difference being the one additional convenience method for resizing the vectors. :p

Quote:

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How can I (Read/Write) (from/to) element (i,j) according to your solution?

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I gave no 'solution', I marely made a suggestion, in trying to understand the problem.
As Jpn hinted, what I suggested was a principal - which is why I asked what you need it for, since sometimes insted of string 'matrxes' string maps might be better, depending on needs.
If the principal of a 2D vector is good foryou , then making the wrapper class you got from qt-interest is trivial.
Oh, and reading/wiring to the bare QVector< QVector<QString> > is tright forword.
objs[i][j] = someString.
Resizing is offered by QVector. as you can see your self in the class you posted.

exectution failed ,debugger indicte:

Code:

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this[r].resize(columns);

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:crying:

Quote:

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exectution failed ,debugger indicte:

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what do you mean?
Segmentation fault, or compilation problem?
show your code

Code:

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//Q2DVector.h
#include <QVector>
 
template <class type>
class Q2DVector : public QVector< QVector<type> >
{
 
public:
		Q2DVector() : QVector< QVector<type> >(){};
		Q2DVector(int rows, int columns) : QVector< QVector<type> >(rows) {
			for(int r=0; r<rows; r++) {
				this[r].resize(columns);
			}
		};
		virtual ~Q2DVector() {};
};
typedef Q2DVector<QString> Q2DQStringVector; 
typedef Q2DVector<int> Q2DQIntVector;

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nothing in Q2Dvector.cpp

Code:

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//main.cpp
 
...
Q2DQStringVector myStringMatrix(P,Q);
...
myStringMatrix[i][j]= someString;
...

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:o

I have got
Unhandled exception at 0x004244e0 in APP.exe: 0x80000001: Not implemented

Oh right, you can't have a templete class that subclasses QObject.

any suggestion
http://http://www.qtcentre.org/forum...cons/icon5.gif

Ok, this a "solution"

Code:

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//A Matrix (P,Q) sized Of QStrings
QVector<QVector<QString> >  myMatrixOfStrings;
myMatrixOfStrings.resize(P);
for(int r=0; r<P; r++)
{
		myMatrixOfStrings[r].resize(Q);
}

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:)

Quote:

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any suggestion

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Yes, don't make your matrix class a template class :)
Or, make your template class without inheritinig QObject (no signal slots then).

Quote:

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Ok, this a the "solution"

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Which is what I suggested from the start ;)

I think the problem is not QObject (where is it anyway? I don't see any QObjects here), but instead this:

Code:

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this[r].resize(columns);

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As "this" is a pointer, you're trying to use an index operator on a pointer, which doesn't make any sense. Either use at() or dereference "this" first:

Code:

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(*this)[r].resize(columns);

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Quote:

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I think the problem is not QObject (where is it anyway? I don't see any QObjects here),

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Oops... you are right...
Now I see that QVector is not a QObjet...
But I thought (obviously was wrong) that in Qt4 all cllases derived QObject.
Hmm, I better read the docs again...:rolleyes:
Sorry about that. (wrong info).

Quote:

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Originally Posted by high_flyer

Oops... you are right...
Now I see that QVector is not a QObjet...

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QVector is a template class itself, so it couldn't be a QObject.

Quote:

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But I thought (obviously was wrong) that in Qt4 all cllases derived QObject.

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Naaa... QObject is quite heavy, so it's better to avoid it if you don't need it. Besides, you could do multiple inheritance then ("Remember, multiple inheritance is a beautiful thing!" :cool: )

Quote:

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QVector is a template class itself, so it couldn't be a QObject.

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You are right of course, didn't really think it through... :rolleyes: