A tool to pretty-print out a number

print_number.py

from typing import Union


def separate_number(number: str, sep: str = ""):
    result = number[::-1]
    insert_idx = []
    times = 0
    for idx in range(len(number)):
        if idx % 3 == 0:
            insert_idx.append(idx + times)
            times += 1

    for i in insert_idx:
        result = result[:i] + sep + result[i:]

    return result[::-1][:-1]  # Return reversed result, with final separator removed


def print_number(number: Union[float, int] = 0, sep: str = ""):
    if len(sep) > 1:
        print("INVALID SEPARATOR")
    result = str(number)

    if sep:
        result = separate_number(result, sep)

    return result


print(print_number(4044400, sep=","))