converter.py

"""
Demo program for how black, flake8, and mypy can help you
dev operable Python!
"""

two_digit_words: list[str] = ["ten", "eleven", "twelve"]
hundred: str = "hundred"
large_sum_words: list[str] = [
    "thousand",
    "million",
    "billion",
    "trillion",
    "quadrillion",
    "quintillion",
    "sextillion",
    "septillion",
    "octillion",
    "nonillion",
]
one_digit_words: dict[str, list[str]] = {
    "0": ["zero"],
    "1": ["one"],
    "2": ["two", "twen"],
    "3": ["three", "thir"],
    "4": ["four", "for"],
    "5": ["five", "fif"],
    "6": ["six"],
    "7": ["seven"],
    "8": ["eight"],
    "9": ["nine"],
}


def convert(n: str) -> str:
    """convert() takes an integer and returns number written out in words"""
    word = []

    # Zero is a special case
    if n == "0":
        return "Zero"

    if n.startswith("-"):
        word.append("(negative)")
        n = n[1:]

    if len(n) % 3 != 0 and len(n) > 3:
        n = n.zfill(3 * (((len(n) - 1) // 3) + 1))

    sum_list = [n[i : i + 3] for i in range(0, len(n), 3)]
    skip = False

    for i, num in enumerate(sum_list):
        if num != "000":
            skip = False

        for _ in range(len(num)):
            num = num.lstrip("0")
            if len(num) == 1:
                if (
                    (
                        len(sum_list) > 1
                        or (len(sum_list) == 1 and len(sum_list[0]) == 3)
                    )
                    and i == len(sum_list) - 1
                    and (word[-1] in large_sum_words or hundred in word[-1])
                ):
                    word.append("and")
                word.append(one_digit_words[num][0])
                num = num[1:]
                break

            if len(num) == 2:
                if num[0] != "0":
                    if (
                        len(sum_list) > 1
                        or (len(sum_list) == 1 and len(sum_list[0]) == 3)
                    ) and i == len(sum_list) - 1:
                        word.append("and")
                    if num.startswith("1"):
                        if int(num[1]) in range(3):
                            word.append(two_digit_words[int(num[1])])
                        else:
                            number = one_digit_words[num[1]][
                                1 if int(num[1]) in range(3, 6, 2) else 0
                            ]
                            word.append(
                                number + ("teen" if not number[-1] == "t" else "een")
                            )
                    else:
                        word.append(
                            one_digit_words[num[0]][
                                1 if int(num[0]) in range(2, 6) else 0
                            ]
                            + ("ty " if num[0] != "8" else "y ")
                            + (one_digit_words[num[1]][0] if num[1] != "0" else "")
                        )
                    break
                else:
                    num = num[1:]
                    continue

            if len(num) == 3:
                if num[0] != "0":
                    word.append(one_digit_words[num[0]][0] + " " + hundred)
                    if num[1:] == "00":
                        break
                num = num[1:]

        if len(sum_list[i:]) > 1 and not skip:
            word.append(large_sum_words[len(sum_list[i:]) - 2])
            skip = True

    """
    This section shows the issues with unexpected type changes.
    The original code converts list[str] to str without notice.
    Mypy complains about this, so you can fix it my declaring
    a new variable of type str.
    """
    # # # This block is the original code
    # # Uncomment for type debugging for "word"
    # # print(word, "is of type:", type(word))
    # # print("***")
    # word = " ".join(map(str.strip, word))
    # # Uncomment for type debugging for "word"
    # print(word, "is of type:", type(word))
    # return (
    #     word[0].lstrip().upper() + word[1:].rstrip().lower()
    #     if "negative" not in word
    #     else word[:11].lstrip() + word[11].upper() + word[12:].rstrip().lower()
    # )
    # This block is the fix for mypy
    print(word, "is of type:", type(word))
    result_word = " ".join(map(str.strip, word))
    # Uncomment for type debugging for "word"
    # print(word, "is of type:", type(word))
    # print(result_word, "is of type:", type(result_word))
    return (
        result_word[0].lstrip().upper() + result_word[1:].rstrip().lower()
        if "negative" not in result_word
        else result_word[:11].lstrip()
        + result_word[11].upper()
        + result_word[12:].rstrip().lower()
    )


if __name__ == "__main__":
    while True:
        try:
            n = input("Enter any number to convert it into words or 'exit' to stop: ")
            if n == "exit":
                break
            int(n)
            print(n, "-->", convert(n))
        except ValueError:
            print("Error: Invalid Number!")