Updating GUI element (QTableview) with QThread, with conditionally setting dataframe

[alan02011114]

In this program I would like to update the QTableview, by setting up a worker thread to process the calculation of new dataframe

from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from PyQt5.QtCore import *
import pandas as pd
import datetime as dt
import numpy as np
import sys

#### Some functions to create different dataframe
def function1(a,b,c):
    df = pd.DataFrame(np.array([[4, 2, 3], [4, 6, 4], [8, 87, 9]]), columns=[a, b, c])
    return df

def function2(a,b,c):
    df = pd.DataFrame(np.array([[4, 2, 3], [4, 6, 4], [8, 87, 9]]), columns=[a, b, c])
    return df


#### Create Worker Thread
class Worker(QThread):
    worksignal = pyqtSignal(pd.DataFrame)

    def __init__(self, parent=None, *args, **kw):
        super(QThread, self).__init__()
        self.passargu(*args, **kw)

    @pyqtSlot(pd.DataFrame)
    def run(self):
        print("Start")
       
        if self.type == "function1":
            self.df = function1(self.para1,self.para2,self.para3)  
        elif self.type == "function2": 
            self.df = function2(self.para1,self.para2,self.para3)

        self.worksignal.emit(self.df)

    def passargu(self, type ,para1, para2, para3):
        self.type =  type
        self.para1 = para1
        self.para2 = para2
        self.para3 = para3

#### Create TableModel for viewing dataframe in QTableview object
class TableModel(QAbstractTableModel):
    def __init__(self, data):
        super(TableModel, self).__init__()
        self._data = data

    def data(self, index, role):
        if role == Qt.DisplayRole:
            value = self._data.iloc[index.row(), index.column()]
            return str(value)

    def rowCount(self, index):
        return self._data.shape[0]

    def columnCount(self, index):
        return self._data.shape[1]

    def headerData(self, section, orientation, role):
        # section is the index of the column/row.
        if role == Qt.DisplayRole:
            if orientation == Qt.Horizontal:
                return str(self._data.columns[section]).replace("\n", " ")
            if orientation == Qt.Vertical:
                return str(self._data.index[section]).replace("\n", " ")

#### Main Gui
class Gui(QWidget):

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

        self.initUI()

    def initUI(self):
        layout = QFormLayout()
        self.add_button1 = QPushButton('UPDATE TABLE - FUNCTION1')
        self.add_button2 = QPushButton('UPDATE TABLE - FUNCTION2')

        self.para1 = QComboBox()
        self.para1.addItems([" ","A","B","C"])
        
        self.para2 = QComboBox()
        self.para2.addItems([" ","D","E","F"])

        self.para3 = QComboBox()
        self.para3.addItems([" ","X","Y","Z"])

        layout.addRow(self.add_button)
        layout.addRow(self.para1)
        layout.addRow(self.para2)
        layout.addRow(self.para3)


        self.table = QTableView()
        layout.addRow(self.table)

        self.setLayout(layout)
        self.add_button1.clicked.connect(lambda: self.threadworker(type="function1"))
        self.add_button2.clicked.connect(lambda: self.threadworker(type="function2"))

    
    def threadworker(self, dfreceived, type):
        self.worker = Worker(self, type, self.para1.currentText(), self.para2.currentText(), self.para3.currentText())
        self.worker.start()
        self.worker.worksignal.connect(self.update_table_gui)

    def update_table_gui(self, df):
        model = TableModel(df)  
        self.table.setModel(model)

def main():
    app = QApplication(sys.argv)
    main = Gui()
    main.show()
    sys.exit(app.exec())
        
if __name__ == "__main__":   
    main()

Error message:

self.add_button1.clicked.connect(lambda: self.threadworker(type="function1"))
TypeError: threadworker() missing 1 required positional argument: 'dfreceived'

In function threadworker I have added a type variable to define which function (function1 or function2) the Worker Thread Worker to be used to calculate the dataframe and then update the QTableview.

dfreceived is used to received the signal from worker thread.
However, if threadworker is assigned to button with lambda (since type is required to tell which function to be used), the error shows up.

[JonB]

@alan02011114
I don't understand what your question is. As the error message tells you, your slot requires a dfreceived/second position argument and you are not supplying it in your lambda so you get the error.