For Python 3

Write a program that converts a number from numerical form to string form. For example you input 123 it prints "one hundred twenty three".

I have this code but my sub thousand method is not working and it says:

Traceback (most recent call last): line 75, in print (subThousand(strNum)) line 28, in subThousand return ByOne[dig] + " hundred" TypeError: list indices must be integers or slices, not float

I marked the lines mentioned in the error with "****************"

ByOne = ["zero","one","two","three","four","five","six","seven","eight","nine","ten","eleven","twelve","thirteen","fourteen", "fifteen","sixteen","seventeen","eighteen","nineteen"] ByTen = ["zero", "ten", "twenty","thirty","forty","fifty","sixty","seventy","eighty","ninety"] zGroup = ["", "thousand","million","billion",] strNum = (input("Please enter an integer: ")) # A recursive function to get the word equivalent for numbers under 1000. def subThousand(inputNum): num = int(inputNum) if 0 <= num <= 19: return ByOne[num] elif 20 <= num <= 99: if inputNum[-1] == "0": return ByTen[int(inputNum[0])] else: return ByTen[int(inputNum[0])] + "-" + ByOne[int(inputNum[1])] elif 100 <= num <= 999: rem = num % 100 dig = num / 100 if rem == 0:  return ByOne[dig] + " hundred" *************************** else: return ByOne[dig] + " hundred and " + subThousand(str(rem)) # A looping function to get the word equivalent for numbers above 1000 # by splitting a number by the thousands, storing them in a list, and # calling subThousand on each of them, while appending the correct # "zero-group". def thousandUp(inputNum): num = int(inputNum) arrZero = splitByThousands(num) lenArr = len(arrZero) - 1 resArr = [] for z in arrZero[::-1]: wrd = subThousand(str(z)) + " " zap = zGroup[lenArr] + ", " if wrd == " ": break  elif wrd == "zero ": wrd, zap = "", "" resArr.append(wrd + zap) lenArr -= 1 res = "".join(resArr).strip() if res[-1] == ",": res = res[:-1] return res # Function to return a list created from splitting a number above 1000. def splitByThousands(inputNum): num = int(inputNum) arrThousands = [] while num != 0: arrThousands.append(num % 1000) num /= 1000 return arrThousands ### Last part is pretty much just the output. intNum = int(strNum) if intNum < 0: print ("Minus",) intNum *= -1 strNum = strNum[1:] if intNum < 1000: print (subThousand(strNum))********************************** else: print (thousandUp(strNum))