title: How can I have the matplotlib graph with pandas.plot() in the widget?
body: <p>So far I have this code: 
  When it's executed, you'll see two windows main and another one called Figure 1, when the csv data is readed, and the plot button pressed, 
  The graph is shown in another window (Figure 2) 
  How can I fix this issues? Many, many thanks in advance for your time!</p>
  
  <pre><code>import sys
  import pandas as pd
  import matplotlib
  matplotlib.use('QT5Agg')
  from PyQt5 import QtWidgets
  from PyQt5.QtWidgets import QDialog, QApplication, QPushButton, QVBoxLayout
  from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
  from matplotlib.backends.backend_qt5agg import NavigationToolbar2QT as NavigationToolbar
  import matplotlib.pyplot as plt
  from matplotlib import style
  style.use('ggplot')
  
  
  class Window(QtWidgets.QMainWindow):
      def __init__(self):
          super().__init__()
          self.initUI()
  
      def initUI(self):
          self.setGeometry(600,300, 1000, 600)
          self.center()
          grid = QtWidgets.QGridLayout()
          widget = QtWidgets.QWidget(self)
          self.setCentralWidget(widget)
          widget.setLayout(grid)
           #Import CSV Button
          btn1 = QtWidgets.QPushButton('Import CSV', self)
          btn1.resize(btn1.sizeHint())
          btn1.clicked.connect(self.getCSV)
          grid.addWidget(btn1, 1, 0)
  
          self.figure = plt.figure(figsize=(15,5))    
          self.canvas = FigureCanvas(self.figure)     
          grid.addWidget(self.canvas, 2,0,1,2)
  
  
          btn2 = QtWidgets.QPushButton('Plot', self)
          btn2.resize(btn2.sizeHint())    
          btn2.clicked.connect(self.plot)
          grid.addWidget(btn2, 1, 1)
          self.show()
  
      def plot(self):
          self.df.plot(x='col1',y='col2')
          self.canvas.draw()
  
      def getCSV(self):
           filePath, _ = QtWidgets.QFileDialog.getOpenFileName(self, 'Open file', '/home')
           if filePath != "":
              print ("Dirección",filePath)
              self.df = pd.read_csv(str(filePath))
  
      def center(self):
          qr = self.frameGeometry()
          cp = QtWidgets.QDesktopWidget().availableGeometry().center()
          qr.moveCenter(cp)
          self.move(qr.topLeft())
  
  def main():
      app = QtWidgets.QApplication(sys.argv)
      w = Window()
      sys.exit(app.exec_())
  
  
  if __name__ == '__main__':
     main()
  </code></pre>