tkinter - how to bind just control, not control+key?

Question

In Python 3 Tkinter, how do I bind just the control key to a widget, not <control-key>?
Normally, it's required to have another key also bound to it.

Answer 1

You would have to bind <Control_L> and <Control_R>

import tkinter as tk

def on_press(event):
    print(event)

root = tk.Tk()
root.bind('<Control_L>', on_press)
root.bind('<Control_R>', on_press)
root.mainloop()

Eventually you can use <Key> which is executed with every key and then check event.keysym or event.code

import tkinter as tk

def on_press(event):
    print(event)
    print(event.keysym in ('Control_L', 'Control_R'))
    print(event.keycode in (37, 105))

root = tk.Tk()
root.bind('<Key>', on_press)
root.mainloop()