convert_number_to_words.py

numbers_in_words = {
    1: "one",
    2: "two",
    3: "three",
    4: "four",
    5: "five",
    6: "six",
    7: "seven",
    8: "eight",
    9: "nine",
    10: "ten",
    11: "eleven",
    12: "twelve",
    13: "thirteen",
    14: "fourteen",
    15: "fifteen",
    16: "sixteen",
    17: "seventeen",
    18: "eighteen",
    19: "nineteen",
    20: "twenty",
    30: "thirty",
    40: "forty",
    50: "fifty",
    60: "sixty",
    70: "seventy",
    80: "eighty",
    90: "ninety",
}

def convert_number_to_text(number: int) -> str:
    if number in numbers_in_words:
        return numbers_in_words[number]

    result = ""

    if number >= 1000:
        thousands, remainder = divmod(number, 1000)
        result = f"{convert_number_to_text(thousands)} thousand"
        if remainder > 0:
            result += f" {convert_number_to_text(remainder)}"
        return result.strip()

    if number >= 20:
        tens, ones = divmod(number, 10)

        if tens <= 9:
            if ones == 0:
                result = numbers_in_words[tens * 10]
            else:
                result = f"{numbers_in_words[tens * 10]} {numbers_in_words[ones]}"

        else:
            hundreds, tens = divmod(number, 100)
            if hundreds <= 9:
                if tens == 0:
                    result = f"{numbers_in_words[hundreds]} hundred"
                else:
                    result = f"{numbers_in_words[hundreds]} hundred {convert_number_to_text(tens)}"

    return result.strip()


if __name__ == "__main__":
    assert convert_number_to_text(5) == "five"
    assert convert_number_to_text(10) == "ten"
    assert convert_number_to_text(11) == "eleven"
    assert convert_number_to_text(12) == "twelve"
    assert convert_number_to_text(13) == "thirteen"
    assert convert_number_to_text(14) == "fourteen"
    assert convert_number_to_text(15) == "fifteen"
    assert convert_number_to_text(20) == "twenty"
    assert convert_number_to_text(31) == "thirty one"
    assert convert_number_to_text(87) == "eighty seven"
    assert convert_number_to_text(100) == "one hundred"
    assert convert_number_to_text(219) == "two hundred nineteen"
    assert convert_number_to_text(999) == "nine hundred ninety nine"
    assert convert_number_to_text(1000) == "one thousand"
    assert convert_number_to_text(1354) == "one thousand three hundred fifty four"
    assert convert_number_to_text(123456) == "one hundred twenty three thousand four hundred fifty six"