# Tk_OptionMenu_swap.py

# Tk_OptionMenu_swap.py

from Tkinter import *

def reset_option_menu(options, index=None):
    '''reset the values in the option menu

    if index is given, set the value of the menu to
    the option at the given index
    '''
    menu = om["menu"]
    menu.delete(0, "end")
    for string in options:
        menu.add_command(label=string,
                         command=lambda value=string:
                              om_variable.set(value))
    if index is not None:
        om_variable.set(options[index])
#
def use_colors():
    '''Switch the option menu to display colors'''
    reset_option_menu(["Red","Orange","Green","Blue"], 0)
#
def use_sizes():
    '''Switch the option menu to display sizes'''
    reset_option_menu(["X-Small", "Small", "Medium", "Large"], 0)
#

root = Tk()

om_variable = StringVar()

b1 = Button(text="Colors", width=8, command=use_colors)
b2 = Button(text="Sizes", width=8, command=use_sizes)

om = OptionMenu(root, om_variable, ())
om.configure(width=20)
use_colors()

b1.pack(side="left")
b2.pack(side="left")
om.pack(side="left", fill="x", expand=True)


mainloop()