Source code for kyu_7.significant_figures.number_of_sigfigs

#  Created by Egor Kostan.
#  GitHub: https://github.com/ikostan
#  LinkedIn: https://www.linkedin.com/in/egor-kostan/


def number_of_sigfigs(number: str) -> int:
    """
    return the number of sigfigs in the
    passed in string "number"
    :param number:
    :return:
    """

    number = normalize_string(number)
    if number == '0':
        return 0
    if number == '0.0':
        return 1

    result = 0
    for i, char in enumerate(number):

        if char.isdigit() and not (i == 0 and char == '0'):
            result += 1

    return result


def normalize_string(number: str) -> str:
    """
    Normalize string by converting it into a
    number and back to string once again
    :param number:
    :return:
    """

    if '.' not in number:
        number = str(int(number))
        number = remove_extra_zeroes(number)
    else:
        number = remove_extra_leading_zeroes(number)

    return number


def remove_extra_zeroes(number: str) -> str:
    """
    Remove all zeroes from the end of the string
    :param number:
    :return:
    """

    index = None

    for i in range(-1, len(number) * -1, -1):
        if number[i] == '0':
            index = i
        else:
            break

    if index is not None:
        return number[0:index]

    return number


def remove_extra_leading_zeroes(number: str) -> str:
    """
    Remove all extra leading zeroes from the head of the string
    :param number:
    :return:
    """
    new_number = str(float(number))

    after_dot = len(number[number.index('.'):])
    new_after_dot = len(new_number[new_number.index('.'):])

    if after_dot == new_after_dot:
        return new_number
    else:
        return new_number + ('0' * (after_dot - new_after_dot))