tk_variables.py

import tkinter as tk
from functools import partial
import tkinter.font as tkfont

class App(tk.Frame):
    def __init__(self, master):
        super().__init__(master)
        
        self.basicFont = tkfont.Font(family='Lucida Grande', size=30)
        
        self.makeLabels()
        self.config(bg="#FFCCCC", width=300, height = 300)
        self.pack(fill=tk.BOTH, expand=1)
        
    def makeLabels(self):
        self.firstLabel = tk.Label(self, text="I'm a variable label!", font=self.basicFont, bg="#CCFFCC")
        self.firstLabel.pack(fill=tk.X, expand=1)
        
        self.myVar = tk.StringVar()
        self.myVar.trace_add("write", self.textchange)
        self.entry = tk.Entry(self, textvariable=self.myVar)        
        self.entry.pack()       
        
        
    def textchange(self, *args):
        self.firstLabel['text'] = self.myVar.get()

if __name__ == '__main__':
    
    myApp = App(tk.Tk())
    myApp.mainloop()