Is it possible to pass a variable of type 'type' to a ComboBox so that all the elements of the collection are selectable?

Question

I am trying to create a GUI app that lets me plot any variable against any other variable. This is my first GUI app, so perhaps I'm biting more than I can chew. The values of these variables are in arrays, which I have grouped into collections -- that is , I use collections.nametuple to group the raw values, the calculated magnitude and phase, the peak index, and a normalized values (please forgive me if I'm not using the correct terminology), for example.

What I would like to do is to have all these variables (or elements of the various collections(?) as choices in two ComboBoxes, xdata and ydata, so that I can plot any variable against any other variable. Is this even possible to do? This is the MainWindow of the app I'm trying to create:

I have the selection of the file, and the parsing of the data working, and for example, say I created these two collections from the data in the file:

type_aData = collections.namedtuple('type_aData',
                                        'A_RX '
                                        'A_RXlogmag '
                                        'A_RXmag'
                                        'A_RXph'
                                        'A_pkMagInd'
                                        'A_RXlogmag_N'
                                        'A_RXmag_N'
                                        'A_RX_N'
                                        'A_RXph_N')



type_distance = collections.namedtuple('type_distance',
                                     'A'
                                     'B')

each A_x is an array, and so are distanceA and distanceB. I'd like to do something like:

self.xdata.addItem(type_distance)
self.ydata.addItem(type_adata)

so that the all the distance variables and aData variables are exposed in the x and y data ComboBoxes, but it complains that the arguments cannot be of type 'type'. If I instead use 'type_distance', for example, in quotes, then all I get is the text in the ComboBox and not the actual variables (never mind that I still don't know how to grab the value selected from the ComboBox to do something with it --that's the next hurdle!).

In short, what I'd like to ultimately be able to do is select the variables I want to plot from the x and y data ComboBoxes so that I can use them in a function that would do something like:

self.data_line=self.graphWidget.plot(self.distance.A, self.aData.A_RX)

or

self.data_line=self.graphWidget.plot(self.distance.A, self.aData.A_RXph),

for example.

If anyone can point me to examples of simple GUI apps that do something similar to what I'm trying to do here , that would be great. I"m not married to doing it this way ---I just don't know any better. I get the feeling I'm complicating this way more than it needs to be.

Answer 1

I'm not sure if this is what you have in mind, but here is a small example to illustrate how you can add the fields of a namedtuple to a QComboBox and use the currently selected fields in these combo boxes to plot the corresponding data in a matplotlib figure:

from PyQt5 import QtWidgets
from collections import namedtuple
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure
import numpy as np


type_distance = namedtuple('type_aData', ['A_RX', 'A_RXlogmag', 'A_RXmag'])
type_aData = namedtuple('type_aData', ['A', 'B'])


class Widget(QtWidgets.QWidget):

    def __init__(self, parent=None):
        super().__init__(parent)

        # setup matplotlib figure
        self.figure = Figure()
        self.ax = self.figure.add_subplot(111)
        self.canvas = FigureCanvas(self.figure)

        # setup rest of ui
        self.combo_x = QtWidgets.QComboBox(self)
        self.combo_y = QtWidgets.QComboBox(self)
        hlayout = QtWidgets.QHBoxLayout()
        hlayout.addWidget(self.combo_x)
        hlayout.addWidget(self.combo_y)

        vlayout = QtWidgets.QVBoxLayout(self)
        vlayout.addWidget(self.canvas)
        vlayout.addLayout(hlayout)

        # generate some random data
        self.distance, self.data = self.generate_data()

        # add field names of data to comboboxes
        self.combo_x.addItems(self.distance._fields)
        self.combo_y.addItems(self.data._fields)

        # connect signals to slot to automatically update plot when selected fields have changed
        self.combo_x.currentTextChanged.connect(self.plot)
        self.combo_y.currentTextChanged.connect(self.plot)
        self.plot()

    def plot(self):
        # extract field names and corresponding data that should be plotted
        xlabel = self.combo_x.currentText()
        ylabel = self.combo_y.currentText()

        x_data = getattr(self.distance, xlabel)
        y_data = getattr(self.data, ylabel)

        # update plot with newly selected data
        self.ax.clear()
        self.ax.plot(x_data, y_data, 'ro')
        self.ax.set_xlabel(xlabel)
        self.ax.set_ylabel(ylabel)
        self.figure.tight_layout()
        self.canvas.draw()

    def generate_data(self):
        # generate some random data and return data as type_distance and type_aData objects
        npoints = 300
        x_data = np.random.normal(size=npoints)
        y_data_a = np.random.normal(size=npoints)
        y_data_b = np.sin(x_data)

        distance = type_distance(x_data, np.log(np.abs(x_data)), np.abs(x_data))
        data = type_aData(y_data_a, y_data_b)
        return distance, data


if __name__ == "__main__":
    app = QtWidgets.QApplication([])
    win = Widget()
    win.show()
    app.exec()