converting a number like 50000 into 50k, 1000000 into 1M, etc

print_si.py

from math import log10
import sys

def print_si(number):
    units = ['', 'k', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y']
    thousands = int(log10(number)//3)
    base = number//1000**thousands
    print("%d %s" % (base, units[thousands]))

if __name__ == '__main__':
    print_iso(int(sys.argv[1]))