python - Why do my Tkinter widgets get stored as None?

Question

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Answer 1

The grid, pack, and place methods of every Tkinter widget operate in-place and always return None. This means that you cannot call them on the same line as you create a widget. Instead, they should be called on the line below:

widget = ...
widget.grid(...)

widget = ...
widget.pack(...)

widget = ...
widget.place(...)

So, in your code, it would be:

b[c+(r*10)] = Button(f, text=chr(97+c+(r*10)), command=lambda a=c+(r*10): color(a), borderwidth=1,width=5,bg="white")
b[c+(r*10)].grid(row=r,column=c)