Adding strings (as representation for base 12 numbers) and integrers/ other strings in python

Question

I need to create a calculator that can add numbers in base 12 and with different limits at the differents diggits.

Base 12 sequence: [0,1,2,3,4,5,6,7,8,9,"A","B"]

The limits must be:

• First digit: limit "B"
• Second digit: limit 4

That means you would count like this:[1,2,3,4,5,6,7,8,9,A,B,10,11,...48,49,4A,4B]

but I don´t know how could I make it so that I can sum 2 numbers

I have the following code in python:

list1=[0,1,2,3,4,5,6,7,8,9,"A","B"]
list2=[0,1,2,3,4]
list3=[0,1,2,3,4,5,6,7,8,9,"A","B"]
list4=[0,1,2,3,4]


def calculadora (entrada1, operacion, entrada2):
    #parte de valor 1:
    digito1_1=str(list2[int(entrada1//12)])
    digito1_2=str(list1[int(entrada1%12)])
    valor1=float(digito1_1+digito1_2)
    #parte de valor 2
    digito2_1=str(list2[int(entrada2//12)])
    digito2_2=str(list1[int(entrada2%12)])
    valor2=float(digito2_1+digito2_2)
    if operacion==str("suma") or "+":
        return float(valor1+valor2)
entrada1 = float(input("inserte primer valor"))
operacion=str(input("inserte operación"))
entrada2 = float(input("inserte segundo valor"))
print (calculadora(entrada1,operacion,entrada2))

It works for numbers but wenn I want to sum numbers like 3B, it gives me a ValueError as it is coded as string.

Could someone help me or say me how could I do it to sum such numbers please?

Answer 1

The easiest way to convert a base-12 encoded string to int is via int(string, 12). The reverse is not quite as easy, because Python doesn't seem to have a built-in way to do that. You can use format specifiers for binary, octal, and hex, but not arbitrary bases.

You can get a reversed list of digits using divmod(), which does division with remainder.

def to_digits(x, base):
     while x > 0:
         x, rem = divmod(x, base)
         yield rem

But to round-trip, we want a string. Convert the int to a character (using a string as a lookup table), and join them into a string, then use a negatively-stepped slice to reverse it.

def to_base_12(num):
    return ''.join('0123456789AB'[d] for d in to_digits(num, 12))[::-1]

With a longer lookup table, you could generalize this into higher bases.

Strings are already sequences, but if you want to convert that back to a list, you can just call list() on it. The inverse is that ''.join() method you just saw.

Now that you can convert your base-12 representation to Python int objects and back, you can simply add them with +.