Show Pandas Dataframe on button click in pyqt5

Question

I'm a beginner in python and pyqt5. I'm trying to populate a tableView on clicking the button. On clicking the pushbutton I want to call another class which can generate the table when passing the dataframe. So far code shows nothing but empty tableview.

from PyQt5 import QtCore, QtGui, QtWidgets
import sys
import pandas as pd
from PyQt5.QtWidgets import QApplication, QTableView
from PyQt5.QtCore import QAbstractTableModel, Qt

df=pd.read_csv("testing_tweets.csv" )

Dataframe Class:

class pandasModel(QAbstractTableModel):

  def __init__(self, data):
    QAbstractTableModel.__init__(self)
    self._data = data
    print("in")

  def rowCount(self, parent=None):
    return self._data.shape[0]
    print("in")


  def columnCount(self, parent=None):
    return self._data.shape[1]
    print("in")

  def data(self, index, role=Qt.DisplayRole):
    if index.isValid():
        if role == Qt.DisplayRole:
            return str(self._data.iloc[index.row(), index.column()])
    return None

  def headerData(self, col, orientation, role):
    if orientation == Qt.Horizontal and role == Qt.DisplayRole:
        return self._data.columns[col]
    return None

Main Class:

class Ui_MainWindow(object):
  def extract(self):
    df=pd.read_csv("testing_tweets.csv" )
    app = QApplication(sys.argv)
    model = pandasModel(df)
    view = QTableView()
    view.setModel(model)
    view.resize(800, 600)
    view.show()
    sys.exit(app.exec_())  

  def setupUi(self, MainWindow):
    MainWindow.setObjectName("MainWindow")
    MainWindow.resize(640, 480)
    self.centralwidget = QtWidgets.QWidget(MainWindow)
    self.centralwidget.setObjectName("centralwidget")
    self.tableView = QtWidgets.QTableView(self.centralwidget)
    self.tableView.setGeometry(QtCore.QRect(10, 10, 621, 331))
    self.tableView.setObjectName("tableView")
    self.pushButton = QtWidgets.QPushButton(self.centralwidget)
    self.pushButton.setGeometry(QtCore.QRect(20, 350, 75, 23))
    self.pushButton.setObjectName("pushButton")
    MainWindow.setCentralWidget(self.centralwidget)
    self.menubar = QtWidgets.QMenuBar(MainWindow)
    self.menubar.setGeometry(QtCore.QRect(0, 0, 640, 21))
    self.menubar.setObjectName("menubar")
    MainWindow.setMenuBar(self.menubar)
    self.statusbar = QtWidgets.QStatusBar(MainWindow)
    self.statusbar.setObjectName("statusbar")
    MainWindow.setStatusBar(self.statusbar)

    self.retranslateUi(MainWindow)
    QtCore.QMetaObject.connectSlotsByName(MainWindow)
    self.pushButton.clicked.connect(self.extract)

  def retranslateUi(self, MainWindow):
    _translate = QtCore.QCoreApplication.translate
    MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
    self.pushButton.setText(_translate("MainWindow", "PushButton"))


if __name__ == "__main__":
  import sys
  app = QtWidgets.QApplication(sys.argv)
  MainWindow = QtWidgets.QMainWindow()
  ui = Ui_MainWindow()
  ui.setupUi(MainWindow)
  MainWindow.show()

  sys.exit(app.exec_())

Any help will be highly appreciated!