Understanding of Tkinter Window geometry

Question

to create a fullscreen window in Python through Tkinter i do this:

w, h = window.winfo_screenwidth(), window.winfo_screenheight()
window.geometry("%dx%d+0+0" % (w, h))

And it works, of course. But I'd like to know why it is like this. Why am I typing "%dx%d+0+0"? What does Python read in that command?

Answer 1

w, h = window.winfo_screenwidth(), window.winfo_screenheight()

w, and h are now holding the value of the screen height and width, say 1280, and 920

window.geometry("%dx%d+0+0" % (w, h))

Then it is a straightforward python string formatting (the old fashion way):

window.geometry("1280x920+0+0")

which is a string that tkinter can parse. (welcome to the 1990'es)