from PyQt5 import QtWidgets, QtCore
from pyqtgraph import PlotWidget, plot
import pyqtgraph as pg
import sys # We need sys so that we can pass argv to QApplication
import os
from random import randint

class MainWindow(QtWidgets.QMainWindow):

def __init__(self, *args, **kwargs):
    super(MainWindow, self).__init__(*args, **kwargs)

    self.graphWidget = pg.PlotWidget()
    self.setCentralWidget(self.graphWidget)

    self.x = list(range(100))  # 100 time points
    self.y = [randint(0,100) for _ in range(100)]  # 100 data points

    self.graphWidget.setBackground('w')

    pen = pg.mkPen(color=(255, 0, 0))
    self.data_line =  self.graphWidget.plot(self.x, self.y, pen=pen)
  
         # ... init continued ...
    
            self.timer = QtCore.QTimer()
    
            self.timer.setInterval(50)
    
            self.timer.timeout.connect(self.update_plot_data)
    
            self.timer.start()
    
    
    
        def update_plot_data(self):
    
    
    
            self.x = self.x[1:]  # Remove the first y element.
    
            self.x.append(self.x[-1] + 1)  # Add a new value 1 higher than the last.
    
    
    
            self.y = self.y[1:]  # Remove the first
    
            self.y.append( randint(0,100))  # Add a new random value.
    
    
    
            self.data_line.setData(self.x, self.y)  # Update the data.
            app = QtWidgets.QApplication(sys.argv)
            
            w = MainWindow()
            
            w.show()
            
            sys.exit(app.exec_())