number_to_excel_column.py

"""Convert number (0 indexed) to Excel spread sheet column."""
import string


def number_to_column(number):
    """Convert number (0 indexed) to Excel spread sheet column."""
    if number < 0:
        return ""
    elif number < 26:
        return string.ascii_uppercase[number]

    modulo = number % 26
    number = (number - modulo) // 26 - 1

    return number_to_column(number) + string.ascii_uppercase[modulo]


if __name__ == "__main__":
    base = 26
    exponent = 3
    count = 0

    for i in range(1, exponent + 1):
        count += pow(base, i)

    for i in range(0, count):
        print(i, number_to_column(i))