permutations of a set

permute.py

#!/usr/bin/env python3

import string
import time

print('\033c')

x = string.ascii_uppercase

for a in x:
    for b in x:
        for c in x:
            for d in x:
            print(a,b,c,d,end='\r')
            time.sleep(0.01)
            print('\033c')

#!/usr/bin/env python3

from math import factorial

#   P ( n , r )
# ( P ( n , r ) = n ! / ( n - r ) ! )

def P ( n , r ):
    return int ( factorial ( n ) / factorial ( ( n - r ) ) )