Tkinter Hello World

We will start our Tkinter journey with popular Hello World program.

Tkinter Hello World.py
from sys import version_info
if version_info.major == 2:
    import Tkinter as tk
elif:
    import tkinter as tk
    
app = tk.Tk()
app.title("Hello World")
app.mainloop()

The window will be like this:

Tkinter Hello World

Attention
The name of Tkinter module has changed from Tkinter in Python 2 to tkinter in Python 3. Therefore if you want to write Python 2 and 3 compatible Tkinter codes, you need to check the Python major version number before importing Tkinter.

For Python 2

import Tkinter as tk

For Python 3

import tkinter as tk

In the next line

app = tk.Tk()

The app window that is a main window could have other widgets like labels, buttons, and canvas in itself. It is the parent window of all its widgets.

app.title('Hello World')

It names the main window as “Hello World”.

app.mainloop()

After window instance is created, mainloop() should be called to let window enter the endless loop, otherwise nothing will show up.