title: tkinter, how to get the value of an Entry widget?
body: <p>I'm trying to offer the user the possibility to calculate his profit of his projected sales if the margin has a certain value (.23). The user should be able to enter any value as projected sales:</p>
  
  <pre><code>from tkinter import *
  
  root = Tk()
  
  margin = 0.23
  projectedSales = #value of entry
  profit = margin * int(projectedSales)
  
  #My function that is linked to the event of my button
  def profit_calculator(event):
      print(profit)
  
  
  #the structure of the window
  label_pan = Label(root, text="Projected annual sales:")
  label_profit = Label(root, text="Projected profit")
  label_result = Label(root, text=(profit), fg="red")
  
  entry = Entry(root)
  
  button_calc = Button(root, text= "Calculate", command=profit_calculator)
  button_calc.bind("&lt;Button-1&gt;", profit_calculator)
  
  #position of the elements on the window
  label_pan.grid(row=0)
  entry.grid(row=0, column=1)
  button_calc.grid(row=1)              
  label_profit.grid(row=2)
  label_result.grid(row=2, column=1)
  
  root.mainloop()
  </code></pre>