title: StringVar DoubleVar and others
body: <p>I am very new on Python and I have a problem.
  I try to read my temperature sensor and set the Value in to my Tkinter GUI.</p>
  
  <p>I don't know how to update my label <code>LT</code> with the new value if I update it with my Button <code>B1</code>.</p>
  
  <p>I have tried everything from <code>StringVar</code> to <code>get()</code> and this stuff.</p>
  
  <p>I hope you can help me to find my failure.</p>
  
  <p>Here is my code:</p>
  
  <pre><code>from tkinter import *
  import os
  
  Main = Tk()
  Main.title("HauptmenÃ¼")
  Main.geometry("500x400")
  class Fenster():
  
      def Credit():
          messagebox.showinfo(title="Credits",message="created by T.N v0.1")
          return
  
      def Beenden():
          pExit = messagebox.askyesno(title="Beenden",message="MÃ¶chten Sie\n wirklich beenden?")
          if pExit &gt; 0:
              Main.destroy()
              return
  
      def auslesen(event):
          file = open("/sys/bus/w1/devices/28-041635ad4cff/w1_slave")
          inhalt = file.read()
          trennwoerter = inhalt.split(" ")
          Wert = (trennwoerter[20])
          Temp = (Wert[2:4])
          file.close()
  
  
      labelauslesen = Label(Main,text="Aktuelle Temperatur :")
      labelauslesen.pack()
  
      LT = Label(Main,text=Inhalt)
      LT.pack()
  
      B1 = Button(Main,text="Temperatur auslesen")
      B1.pack()
      B1.bind("&lt;Button-1&gt;",auslesen)
  
      menubar=Menu(Main)
  
      filemenu = Menu(menubar)
      filemenu.add_command(label="Sensoren auslesen")
      filemenu.add_command(label="Diagram anzeigen")
      filemenu.add_command(label="Credits",command = Credit)
      filemenu.add_command(label="Beenden",command = Beenden)
  
      menubar.add_cascade(label="Datei",menu=filemenu)
  
      Main.config(menu=menubar)
  
  
  mainloop()
  </code></pre>