Testing comma-delimited numbers and percentages

numbers.py

import time
import logging


# https://docs.python.org/3/library/decimal.html?#recipes
# this does not work for me


def comma_delimited_value(value=0, right_justify=False):
    """
    :param value: the decimal value to print (0 - 999,999,999)
    :param right_justify: True: print leading spaces to right-justify string (ex., "   ,   ,199"
    :return: None
    print a comma-delimited decimal value, up to 999,999,999
    """
    if 0 > num > 999999999:
        return ValueError
    width = len(str(num))  # should return how many digits in 'num'
    print(f"num = {num}")
    print(f"right_justify = {right_justify}")
    if right_justify:
        if num > 999:
            width += 1   # account for thousands separator
        if num > 999999:
            width += 1   # account for millions separator
            print(f"width = {width}")
        return "           " + str(num)
    return str(num)


def comma_value(value, right_justify):
    # an expert showed me this:
    # >>> print("{:,}".format(3024))
    # 3,024
    # right-justify numbers:
    # >>> print("{:>11}".format("{:,}".format(987654321)))
    # 987,654,321
    # >>> print("{:>11}".format("{:,}".format(100)))
    #         100
    """
    Convert int to a comma-delimited string with "," as a grouping separator
    Optionally right-justify the output
    """
    digits = []
    for d in str(value):
        digits.append(d)
    # reverse list so we can count from tens place, working to the left
    digits.reverse()
    logging.info(digits)
    output = []
    count = 0
    for d in digits:
        # this is really weird, but these next 3 lines need to be in this order to work
        count += 1
        if count == 4 or count == 7:  # and not 3 or 6...
            output.append(",")
        output.append(d)
        # logging.info(f"intermediate: {output}")
    # swap the reversed number around again to make it readable:
    output.reverse()
    # convert list to string:
    string = ''.join(output)
    logging.info(f"string: {string}")
    if right_justify:
        return "           "[:11 - len(string)] + string
    return string


def progress():
    maximum = 10000
    width = len(str(maximum))
    for i in range(maximum+1):  # maximum+1 is a hack to get the progress to 100% instead of 90%
        if i % 100 == 0:
            print(f"\rCompleted {i} of {maximum:{width}} ({i / maximum * 100:3f}%)", flush=True, end='')
            time.sleep(0.25)


if __name__ == '__main__':
    logging.basicConfig(level=logging.DEBUG, format='[%(levelname)s] | %(asctime)s  | %(message)s')
    logging.debug('This is a log message.')
    # my old code:
    # print(f"Gold: {comma_delimited_value(value=1000, right_justify=True)}")
    print(f"Gold: {comma_value(value=10000, right_justify=True)}")
    print(f"Large Value: {comma_value(value=987654321, right_justify=False)}")
    for thing in ['1', '10', '100', '1000', '10000', '100000', '1000000', '10000000', '100000000']:
        print(f"Large Value: {comma_value(value=thing, right_justify=True)}")
    for thing in ['1', '10', '100', '1000', '10000', '100000', '1000000', '10000000', '100000000']:
        print(f"Large Value: {comma_value(value=thing, right_justify=False)}")

    # progress()