str'对象没有属性'get'python

Question

I am coding for use on a raspberry pi. I have something like the following dictionary,

self.appData = {"v": tk.StringVar(), "k": tk.StringVar()} 

Then I set a default value

self.appData["v"].set("G")

Then I have everything setup for keypad input.

In my function that deciphers the key that was pushed, I take the keypad push and it suppose to take the string from the current v (self.appData["v"].get()) and then add the new keypad push to it.

Ex: 1st keypad push is "a", The function that deciphers the keypad button pushed, I have something like the following:

x = self.appData["v"].get() + key
self.appData["v"].set(str(x))

so it should get "G" from the dictionary and the "A" to it. Then I set v to the new x. It works fine the first time, then the second time it goes through that function I get the error:

str' object has no attribute 'get' python

Answer 1

Here you are setting self.appData["w"] as a string:

self.appData["v"].set("G")

This only works because tk.StringVar has a set method. This is not how you assign a value inside a dict. In the same way, this line is wrong:

x = self.appData["v"].get() + key

so you are calling the get() method on a string, and strings don't have a get method. I guess that what you want to do is:

x = self.appData.get("v") + key
self.appData["v"] = x