[Tutor] Simple calculator

[Joe Cox]

I found this simple calculator on the web:

from Tkinter import *
from math import *
###http://sunsite.uakom.sk/sunworldonline/swol-02-1998/swol-02-python.htmlBy
Cameron Laird and Kathryn Soraiz...Getting Started with Python###

def evaluate(event):
        label['text'] = "Result:  " + str(eval(expression.get()))

frame = Frame(None)

entry = Entry(frame)
entry['textvariable'] = expression = StringVar()
entry.bind("", evaluate)

label = Label(frame)

button = Button(frame, text = "Submit", command = evaluate)

frame.pack()
entry.pack()
label.pack()
button.pack()
frame.mainloop()

I get this:

>>> Traceback (most recent call last):
  File
"D:\Python24\Lib\site-packages\pythonwin\pywin\framework\scriptutils.py",
line 310, in RunScript
    exec codeObject in __main__.__dict__
  File "D:\Python24\Calculator\Calc.py", line 12, in ?
    entry.bind("", evaluate)
  File "D:\Python24\lib\lib-tk\Tkinter.py", line 933, in bind
    return self._bind(('bind', self._w), sequence, func, add)
  File "D:\Python24\lib\lib-tk\Tkinter.py", line 888, in _bind
    self.tk.call(what + (sequence, cmd))
TclError: no events specified in binding

Please have a look for me thanks!




Joe Cox
513-293-4830