columbo.py: Excel column letters to numbers and vice versa.

columbo.py

import os

def excel_column_to_number(column: str) -> int:
    """
    Converts a excel column string to ordinal number.
    Ejemplo: "A" -> 1, "B" -> 2, "AA" -> 27
    """
    column = column.upper()  # Uppercase letters
    result = 0
    for char in column:
      # Uses the UTF-8 code for getting the index.
        result = result * 26 + (ord(char) - ord('A') + 1) # letters are technically a base26 system...
    return result


def number_to_excel_column(number: int) -> str:
    """
    Converts a number to the excel column string.
    Example: 1 -> "A", 2 -> "B", 27 -> "AA"
    """
    result = []
    while number > 0:
        number -= 1
        result.append(chr(number % 26 + ord('A')))
        number //= 26
    return ''.join(reversed(result))


# Ejemplo de uso
if __name__ == "__main__":
    # User input and data management
    os.system('cls')
    try:
        while True:
            user_input = input("Place column letters or a number: ").strip()

            # Check if input is a number or column letters
            user_input_parsed = int(user_input) if user_input.isdigit() else user_input.upper()

            # Choose automatically the function to use.
            if type(userinput_parsed) == int:
                print(f"    {number_to_excel_column(userinput_parsed)}")
            else:
                print(f"    {excel_column_to_number(userinput_parsed)}")
    
    # Exit with Ctrl + C            
    except KeyboardInterrupt:
        os.system('cls')
        quit()