[Tkinter] messed callbacks

[John Posner]

<snip>
>  def cb12(): return output(c1+'->'+c2)
>  def cb21(): return output(c2+'->'+c1)

I think these can be simplified, e.g:

   def cb12(): output(c1+'->'+c2)

But I'd go with the functools.partial approach. You can save some code 
by making output() do more of the work:

#---------------------------
from Tkinter import *
from functools import partial

def output(x,y,op):
  if op == "<":
    print x, "<---", y
  elif op == ">":
    print x, "--->", y
  else:
    print "Operation argument error!"

def doit(fr,lst):
  for c1, c2 in zip(lst[::2], lst[1::2]):
    subframe=Frame(fr)
    Label(subframe,text=c1+' <-> 
'+c2).pack(side='left',expand=1,fill='both')
    for op in ('<', '>'):
      Button(subframe,text=op,
             command=partial(output, c1, c2, op)).pack()            
    subframe.pack(fill='x',expand=1)

root=Tk()
doit(root,['pippo','pluto','paperino','zio_paperone'])
Button(root,text='Q',command=root.destroy).pack(expand=1,fill='x')
root.mainloop()
#---------------------------

-John