arbitrarybase.py

import string


class BaseNumber():
    def __init__(self, number=None, numerator=None, denominator=None):
        if numerator and denominator:
            self.numerator = int(numerator)
            self.denominator = int(denominator)
        elif number:
            self.num = float(number)
        self.mapping = string.digits + string.letters

    def _int_to_base(self, num, base):
        if num < 0:
            sign = -1
        elif num == 0:
            return self.mapping[0]
        else:
            sign = 1

        num *= sign
        digits = []

        while num:
            digits.append(self.mapping[num % base])
            num /= base

        if sign < 0:
            digits.append('-')

        digits.reverse()
        return ''.join(digits)

    def base(self, base):
        base = int(base)
        if self.numerator and self.denominator:
            num = 1. * self.numerator / self.denominator
        else:
            num = self.num
        integral, point, fractional = str(num).strip().partition('.')
        num = int(integral + fractional) * 10 ** -len(fractional)
        num = self._int_to_base(int(round(num/base ** -len(fractional))), base)
        return num[:-len(fractional)] + '.' + num[-len(fractional):]

    def __repr__(self):
        if self.numerator and self.denominator:
            return str(self.numerator)+"/"+str(self.denominator)
        else:
            return str(self.num)


given = raw_input().split(' ')

a = BaseNumber(numerator=given[0], denominator=given[1])
print a.base(given[2])