Division Demo

division_demo.py

#!/usr/bin/python

# Example usage:
#   $ ./division_deom.py 1 7
#   0 1
#   .
#   1 3
#   4 2
#   2 6
#   8 4
#   5 5
#   7 1
#
#   $ ./division_demo.py 1 9801 --chunk 2
#   0 1
#   .
#   00 10 100
#   01 1000 199
#   02 1990 298
#   03 2980 397
#   ...
#   96 6841 9604
#   97 7831 9703
#   99 8821 1

import argparse
parser = argparse.ArgumentParser()
parser.add_argument('numer', type=int)
parser.add_argument('denom', type=int)
parser.add_argument('-c', '--chunk', type=int, default=1)
args = parser.parse_args()

def divison_residues(n, d, base=10):
    while True:
        q, r = divmod(n, d)
        yield q, r
        n = r * base

def until_repeated_residue(digit_residues):
    first = None
    for digit, residue in digit_residues:
        if first is None:
            if residue != 0:
                first = residue
        elif residue == first:
            break
        yield digit, residue

from itertools import islice
def chunk(n, iterable):
    while True:
        c = tuple(islice(iterable, n))
        if not c:
            break
        yield c

digit_residues = divison_residues(args.numer, args.denom)
unit, residue = next(digit_residues)
print(unit, residue)
print('.')

digit_residues = until_repeated_residue(digit_residues)

if args.chunk == 1:
    for digit, residue in digit_residues:
        print(digit, residue)
else:
    for drs in chunk(args.chunk, digit_residues):
        digits, residues = zip(*drs)
        print(''.join(map(str, digits)), *residues)