What is the difference between a variable and StringVar() of tkinter ?

Question

Program :

import tkinter as tk

b = "hi"

print(b)

b1 = tk.StringVar()

b1.set("Hi")

print(b1)

This is the output I'm getting :

hi ##(Output from first print function) 

AttributeError: 'NoneType' object has no attribute '_root' (Output from second print function) 

My question is, I just need to know the difference between b and b1 in the above code and I just need to know why a1 is giving me an error?

Answer 1

Basically, the StringVar() method is used for editing a widget's text

Example:

import tkinter as tk

root = tk.Tk()

my_string_var = tk.StringVar()

my_string_var.set('First Time')

tk.Label(root, textvariable=my_string_var).grid()

root.mainloop()

Here, We will be having an output with a label saying First time

Note:-

We have to use textvariable when we are using string variables

Check this code:-

import tkinter as tk

def change():

    my_string_var.set('Second Time')

root = tk.Tk()

my_string_var = tk.StringVar()

my_string_var.set('First Time')

tk.Label(root, textvariable=my_string_var).grid()

tk.Button(root, text='Change', command=change).grid(row=1)

root.mainloop()

Here you see, This code produces a label saying First Time and also a button to change it to Second Time

See, with the help of a normal variable, we can't achieve this, only tkinter's StringVar() can do this. 

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