Convert between str using arbitrary base and integer (positive integers only)

int2str.py

DIGITS = (
    string.digits +
    string.ascii_lowercase +
    string.ascii_uppercase +
    string.punctuation
)


def int2str_converter(base):
    assert 2 <= base <= len(DIGITS)
    digits = DIGITS[:base]

    def int2str(int_num):
        assert int_num >= 0

        num_digits = []
        while int_num > 0 or not num_digits:
            int_num, i = divmod(int_num, len(digits))
            num_digits.append(digits[i])
        return "".join(reversed(num_digits))
    return int2str


def str2int_converter(base):
    assert 2 <= base <= len(DIGITS)
    digits = DIGITS[:base]

    def str2int(str_num):
        int_num = 0
        o = len(str_num) - 1
        for i, digit in enumerate(str_num):
            assert digit in digits
            int_num += digits.index(digit) * (base ** (o - i))

        return int_num
    return str2int


i2s2 = int2str_converter(base=2)
i2s8 = int2str_converter(base=8)
i2s16 = int2str_converter(base=16)
i2s36 = int2str_converter(base=36)
i2s62 = int2str_converter(base=62)
i2s94 = int2str_converter(base=94)

s2i2 = str2int_converter(base=2)
s2i8 = str2int_converter(base=8)
s2i16 = str2int_converter(base=16)
s2i36 = str2int_converter(base=36)
s2i62 = str2int_converter(base=62)
s2i94 = str2int_converter(base=94)