Евгений

from tkinter import *


root = Tk()

entr = Entry(root)
entr.pack()

def foo(e):
    s = entr.get().strip()
    s = s[-1] if s else ''
    entr.delete ('0',END)
    entr.insert(INSERT,s)
    print (e.char)

entr.bind('<KeyRelease>',foo)


entr2 = Entry(root)
entr2.pack()

def foo2(e):
    entr2.delete ('0',END)
    print (e.char)

entr2.bind('<KeyPress>',foo2)



root.mainloop()