Create a program to convert hexadecimal in decimal (python)

Question

I have to create a program in Python that will convert a hexadecimal number to a decimal number, for example from FA2 to 4002.

I have to write the function hexa2dec(c) where c is a string input parameter and the returned value is of type int. I've started by creating a dictionary :

dic={"0":0, "1":1, "2":2, "3":3, "4":4, "5":5, "6":6, "7":7, "8":8, "9":9, "A":10, "B":11, "C":12, "D":13, "E":14, "F":15}

and my code is this:

c = "F"

def hexa2dec(c):

   d = ""   

   if c[0]=="F":

      d = dic["F"]*(16**(len(c)-1))

  return d

But I know that it's very bad, for example I don't know what will the length that a person can enter if this person for example does print(hexa2dec(F4CF)). I know that with len(i) I can know the length but does it help ?

Possible duplicate [Convert hex string to int in Python](https://stackoverflow.com/questions/209513/convert-hex-string-to-int-in-python) — Alif Jahan, Jan 28 '19 at 16:58
thank you for your awnser but my professor wants that we do it with a function — LaProduction Sashimine, Jan 28 '19 at 16:58
If you search on the phrase "Python convert hex to decimal" or "Python convert base", you’ll find resources that can explain it much better than we can in an answer here. — Prune, Jan 28 '19 at 17:08
@BoarGules, it doesn't say that anywhere in the question. Most people want the best and easiest fix. — I Funball, Jan 28 '19 at 17:14
@BoarGules I assume the answers drew the conclusion from *"thank you for your awnser but my professor wants that we do it with a function"*, which was written after I made my comment. — iz_, Jan 28 '19 at 17:19
@BoarGules Can you please double check your math? The comment was 25 mins ago, the answers 20 mins ago. — iz_, Jan 28 '19 at 17:23
no i just want help, sorry if you think that i want people do everything for me — LaProduction Sashimine, Jan 28 '19 at 17:31

score 0 · Answer 1 · answered Jan 28 '19 at 17:03

Since this is a task set to you by your professor, I'm not going to solve it for you, I'll just give you a few hints:

You can iterate over a string backwards using slice/stride notation: for digit in hex_string[::-1]: will do that.

Now you can use a counter variable, use it to calculate the correct power of 16, and increment it in each loop. If you already know the enumerate() function, that task becomes even easier.

Use a result variable and add the result of each iteration to it.

That should get you started.

thanks you, i'm not asking for people do all the work for me. I asked for clues :) — LaProduction Sashimine, Jan 28 '19 at 17:24

score 0 · Answer 2 · answered Jan 28 '19 at 17:04

0

The better way would be to just use one of the preprogrammed functions but since you want to code it yourself, I suggest you try using loops. For example a while loop to perform some math on every digit.

answered Jan 28 '19 at 17:04

Alberto Sánchez

1

Create a program to convert hexadecimal in decimal (python)

2 Answers2