How can i get y value from a plotted QCustomPlot?

pedromenezes

Hi,

My data is already plotted on:

ui->cumstomPlot_1

And now i need to read this data (256 "y" values), sum each value ( from this y axis) and write a new file with this this code:

for(int i=0; i<257; ++i)
    {
//Here I want to create a new double ("new_y") variable to receive the y value indexed by "i"  (in this case my "x" axis)
        double r =  QRandomGenerator::global()->bounded(-100,100);
        df<< QString("%1").arg(i) + "," + QString("%1").arg(new_y+(r/10));
        df <<"\n";

        qDebug() << r;
    }
//from this point on, i know what I  must have to do.

Thanks

pedromenezes

Hi,
Someone could help me, please!!!

mrjj

Hi
Actually QCustomPlot is not part of Qt and have its own support forum.
https://www.qcustomplot.com/index.php/support/forum

We would tell you if we knew but so far no user seems to know the answer here.

pedromenezes

Ok. Thanks.

pedromenezes

@mrjj I solved the problem and I will post here just in case someone needs:

...

    for (int i=0;i<256;++i){
     double lastKey = (ui->customPlot_1->graph(0)->data()->at(i)->key);
     double lastValue = (ui->customPlot_1->graph(0)->data()->at(i)->value);
     qDebug () << "X:" << i << lastKey;
     qDebug () << "Y:" << i << lastValue;
}

SGaist

Hi,

You can improve your access to the data using:

auto plotData = ui->customPlot_1->graph(0)->data();
for (int i = 0 ; i < plotData->size() ; ++i) {
     double lastKey = plotData->at(i)->key;
     double lastValue = plotData->at(i)->value);
     qDebug () << "X:" << i << lastKey;
     qDebug () << "Y:" << i << lastValue;
}

Or use iterators.