Updating text on a label - python-3.x

Question

I am working through an Oreilly Tutorial on tkinter, but the code provided in the tutorial doesn't work for me. The "Choose one" message doesn't show, instead it shows: PY_VAR0. When I click the hello button nothing happens. When I click the goodbye button the window closes as expected but no message is shown.
Of note, prior I had:
def say_hello(self):
self.label.configure(text="Hello World!")
def say_goodbye(self):
self.label.configure(text="Goodbye! \n (Closing in 2 seconds)")
self.after(2000, self.destroy)
And received an attribute error: attributeerror: '_tkinter.tkapp' object has no attribute 'label' site:stackoverflow.com.
I am uncertain what is wrong as I have followed the example explicitly in both cases.
My code is below:
import tkinter as tk
class Window(tk.Tk):
def __init__(self):
super().__init__()
self.title('Hello Tkinter')
self.label_text = tk.StringVar()
self.label_text.set("Choose One")
label = tk.Label(self, text=self.label_text)
label.pack(fill=tk.BOTH, expand=1, padx=100, pady=30)
hello_button = tk.Button(self, text='Say Hello',
command=self.say_hello)
hello_button.pack(side=tk.LEFT, padx=(20, 0), pady=(0, 20))
goodbye_button = tk.Button(self, text ='Say Goodbye',
command=self.say_goodbye)
goodbye_button.pack(side=tk.RIGHT, padx=(0, 20), pady=(0, 20))
def say_hello(self):
self.label_text.set("Hello World!")
def say_goodbye(self):
self.label_text.set("Goodbye! \n (Closing in 2 seconds)")
self.after(2000, self.destroy)
if __name__ == "__main__":
window = Window()
window.mainloop()

Answer 1

You need to set the label textvariable=self.label_text instead of text=self.label_text
import tkinter as tk
class Window(tk.Tk):
def __init__(self):
super().__init__()
self.title('Hello Tkinter')
self.label_text = tk.StringVar()
self.label_text.set("Choose One")
label = tk.Label(self, textvariable=self.label_text)
label.pack(fill=tk.BOTH, expand=1, padx=100, pady=30)
hello_button = tk.Button(self, text='Say Hello',
command=self.say_hello)
hello_button.pack(side=tk.LEFT, padx=(20, 0), pady=(0, 20))
goodbye_button = tk.Button(self, text ='Say Goodbye',
command=self.say_goodbye)
goodbye_button.pack(side=tk.RIGHT, padx=(0, 20), pady=(0, 20))
def say_hello(self):
self.label_text.set("Hello World!")
def say_goodbye(self):
self.label_text.set("Goodbye! \n (Closing in 2 seconds)")
self.after(2000, self.destroy)
if __name__ == "__main__":
window = Window()
window.mainloop()