这里的 len() 有什么意义？

Question

I'm learning the Pyautogui module, i have came to a script where it print the position of the mouse for you. and delete previous output, so it look like the output is updating.

but i understand everything here but i dont understand what does *len(strPosition) exactly is there for?

#!/usr/bin/env python3
import pyautogui


try : 
    while True:
        x,y = pyautogui.position()
        strPosition = ' X : '+str(x).rjust(4)+' Y : '+str(y).rjust(4)
        print(strPosition,end='')
        print('\b'*len(strPosition) ,end='',flush=True)
except KeyboardInterrupt :

    print('\nDone.')

Answer 1

Constructs like:

print('a string' * NUM)

mean: print 'a string' NUM number of times.