什么。？ （点感叹号）在python中是什么意思？

Question

I wrote the following program:

from tkinter import *

root = Tk()

temp = None
def changeColor(event, e):
    # print('Positional arumgent passed:', x)
    print('event: ', event.widget)
    e2 = event.widget
    if e2['bg'] == 'white':
        e2['bg'] = 'black'
    elif e2['bg'] == 'black':
        e2['bg'] = 'white'
    global temp
    temp = event

entries = [[None for i in range(3)] for j in range(3)]

for y in range(3):
    for x in range(3):
        e = Entry(root, width=3, bg='white', bd=0, borderwidth=3)
        e.bind('<Double-Button-1>', lambda x: changeColor(x, e))
        e.grid(column=x, row=y)
        entries[y][x] = e

root.mainloop()

which, in the terminal, produced the output,

event:  .!entry5
event:  .!entry6
event:  .!entry8
...

When I examined the one of the event.widgets (stored in temp) in the terminal, I got,

>>> temp.widget
<tkinter.Entry object .!entry8>
>>> print(temp.widget)
.!entry8

I've never seen this syntax before and I was unable to find anything in the docs or here on stackoverflow about it.

Does anyone know what it is? Could you kindly explain/describe?

Answer 1

.! is not a general Python thing, it's just how the tkinter library names widgets that are not otherwise given a name. entry comes from here , since this widget is an Entry class. The exclamation point & number suffix are assigned here , presumably being given a ! so that auto-generated, class-name-derived widget names don't overlap with those assigned by the user. And the leading period is how widgets are named when they don't have a named parent; if they did, it would be <parentname>.<childname> .