flipper.py

import sys
import argparse
import itertools as it
import numpy as np


def flipper(n):
    def cool_range_doritos(*args, **kwargs):
        if sys.version_info[0] < 3:
            return xrange(*args, **kwargs)
        else:
            return range(*args, **kwargs)

    flips = [np.random.randint(2) for _ in cool_range_doritos(n)]
    chain_lengths = list(len(list(chain)) for _, chain in it.groupby(flips))
    result = enumerate(np.bincount(chain_lengths))
    next(result)
    return result


def int_greater_than_zero(arg):
    msg = "'{}' is not an integer greater than zero.".format(arg)
    try:
        value = int(arg)
    except ValueError:
        raise argparse.ArgumentTypeError(msg)

    if not value > 0:
        raise argparse.ArgumentTypeError(msg)
    return value


if __name__ == '__main__':
    parser = argparse.ArgumentParser(description="""
                                     Displays the lengths of chains of the same
                                     result after a certain number of coin
                                     flips.""")
    parser.add_argument("num_flips", help="The total number of flips.",
                        type=int_greater_than_zero)
    args = parser.parse_args()

    for pair in flipper(args.num_flips):
        print(pair)