Btukfyl

This is the beginning of my program that calculates simple interest. Interest rate will have the following format : 0.97 , 0.67 , 0.17 etc. They won't be bigger than 1. So if the user enter 9 for the interest, program will convert it to 0.09 (by dividing it by 100) . Also user can enter input using '/'. So program will convert input like 97/100 to 0.97.

I wrote the code below. It works but it seems to me that there might be a easier and more elegant solution to this. Maybe using more build-in functions etc. If you help me with that I would be very appreciated.

def toNum(interest):



    if '/' not in interest:

        if float(interest) > 1:

            return float(interest)/100



        else:

            return float(interest)





    else:

        l= 

        n = 0

        count = 1



        list_interest=

        for e in interest:

            list_interest.append(e)



        for e in list_interest:



            if count == 1 or count == 3:

                l.append(e)

                count = count +1

                continue





            if e == '/':

                n = n + 1

                count = count +1

            else:

                l[n] = l[n] + e



        return int(l[0]) / int(l[1])













interest = input("Interest rate: ")













print(toNum(interest))

This seems to do what you've accomplished, and is reasonably compact.

EDIT added in a recursive function call, because I realised the if/else wasn't really necessary because you can just feed the numerator back in. This assumes, of course, that the numerator/denominator always uses 100 as its denominator.

It determines whether it's possible to float the input. If it can it either divides by 100 or returns, depending on whether the value is > 1. If an Exception is raised (in your case, meaning that the user has entered "97/100" or similar) it parses this out and returns the calculated rate.

There are a bunch of edge cases where this would fail, but it's something to build on/consider.

def toNum(interest):



    try:

        floated = float(interest)

        if floated > 1:

            rate = floated / 100

        elif floated < 1:

            rate = floated

        return rate

    except ValueError:

        return toNum(interest.split("/")[0])

I guess the following might work:

import re

interest = re.sub('[^0-9.0-9]+', '', interest)

print(toNum(interest))

You have two cases, the input is purely numeric, or it is a fraction notation. So check if you have a fraction:

def toNum(user_input):

    if '/' in user_input:

        return abs(eval(user_input))



    if user_input.isnumeric():

        return int(user_input)/100



    raise AttributeError('`user_input` must be an integer 0-100 or fraction')

Since isnumeric() will return false if they input -1 or some garbage like that you're safe there.