title: how to Clear graph tkinter
body: <p>well with this code I want to make dynamic graph, I want to make my graph clear every 60 second, but I cant make it work with cla() and clf(), what is wrong?
  is there any otherway to clear graph except using cla() and clf()?</p>
  
  <pre><code>#import lib client paho mqtt
  from Tkinter import *
  from ttk import *
  from datetime import datetime
  import matplotlib
  import paho.mqtt.client as mqtt
  import redis, time
  from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
  from matplotlib.figure import Figure
  from matplotlib import style 
  import matplotlib.pyplot as plt
  from matplotlib.pyplot import get_current_fig_manager
  
  mqttc = mqtt.Client("serverclient",clean_session=False)#inisialisasi mqtt client
  r = redis.Redis("localhost",6379)
  start = time.time()
  date = datetime.now().strftime('%S')
  f = Figure(figsize=(5,4), dpi=100)
  a = f.add_subplot(111)
  b = f.add_subplot(111)
  style.use('ggplot')
  matplotlib.use("TkAgg")
  suhu=30
  cahaya=50
  
  
  def mqttx():
      #fungsi callback
      def on_message(mqttc,obj,msg):
          global LED1
          global LED2
          datasuhu = r.lrange("suhu",-1,-1)
          datacahaya = r.lrange("cahaya",-1,-1)
          print "Telah Diterima message : "+msg.payload+" topik "+msg.topic
          r.rpush(msg.topic,msg.payload)
  
      mqttc.on_message =  on_message
  
      mqttc.connect("localhost",1883)
  
      mqttc.subscribe("suhu")
      mqttc.subscribe("cahaya")
  
  class Example(Frame):
      def __init__(self, parent):
          Frame.__init__(self, parent)
          self.parent = parent
          self.initUI()
  
          self.graph()
  
      def initUI(self):
  
          self.parent.title("Subcriber")
          self.style = Style()
          self.style.theme_use("default")
          self.pack(fill=BOTH, expand=1)
  
          self.xList1 = []
          self.yList1 = []
          self.canvas = FigureCanvasTkAgg(f, self)
  
          self.canvas.show()
          self.canvas.get_tk_widget().pack(expand=True)
          thismanager = get_current_fig_manager()
          thismanager.window.wm_geometry("+500+0")
  
  
      def graph(self):
          suhu1 = r.lrange("suhu",-1,-1)
          cahaya1 = r.lrange("cahaya",-1,-1)
          date = datetime.now().strftime('%S')
          join1=str(''.join(suhu1))
          suhugraph=float(join1)
  
          join2=str(''.join(cahaya1))
          cahayagraph=float(join2)
  
          self.xList1.append(date)
          self.yList1.append(suhugraph)
          a.clear()
          a.axis([0, 100, 0, 60])
          a.plot(self.xList1, self.yList1,"r-")
  
          if date=="00" :
              plt.clf()
              plt.cla()
          else:
  
              self.canvas.draw()
  
          self.after(1000, self.graph)
  
  def main():
      root = Tk()
      root.geometry("1500x1400+300+300")
      app = Example(root)
  
      root.mainloop()
  
  if __name__ == '__main__':
  
      mqttx()
      mqttc.loop_start()
      main()
  </code></pre>