integer input to string in else statement (Python)

Question

As seen in the code I am trying to convert the fee integer into a string to prevent a ValueError. I only want to display the message "That's not your real age mate," when the user inputs a negative number, a number >100, or a string.

active = True

while active:
    print("How old are you?")
    fee = int(input())

    #Checks age of user to determine the price of a movie ticket
    if 0 <= fee <= 3:
        print("You're free mate")
        active = False

    elif 4 <= fee <= 12:
        print("$10 please!")
        active = False

    elif 13 <= fee <= 64:
        print("$15 please!")
        active = False

    elif 65 <= fee <= 100:
        print("$10 please!")
        active = False

    #convert negative numbers or letters into strings as to not cause a ValueError $ restart the while loop
    else:
        fee = str(fee)
        print("That's not your real age mate")
        continue

Could you pls explain your query? Running the code gives the desired output — Aryan Garg, Jun 09 '21 at 09:59
When I run the code I currently receive a ValueError if I input an string. How do I fix this? — realFishSam, Jun 09 '21 at 09:59
Can you give an example of the integer that is producing an error for you? — Axe319, Jun 09 '21 at 10:00
Does this answer your question? [How to check if string input is a number?](https://stackoverflow.com/questions/5424716/how-to-check-if-string-input-is-a-number) — Axe319, Jun 09 '21 at 10:03
You should first check if input can be converted to int at all, and handle errors. Only if that works should you do the other checks. See this for reference: https://stackoverflow.com/questions/2262333/is-there-a-built-in-or-more-pythonic-way-to-try-to-parse-a-string-to-an-integer — shree.pat18, Jun 09 '21 at 10:03

Dr. Strange Codes · Answer 1 · 2021-06-09T10:13:51.137

To fix value error put exception:-

active = True

try:
 while active:
    print("How old are you?")
    fee = int(input())

    #Checks age of user to determine the price of a movie ticket
    if 0 <= fee <= 3:
        print("You're free mate")
        active = False

    elif 4 <= fee <= 12:
        print("$10 please!")
        active = False

    elif 13 <= fee <= 64:
        print("$15 please!")
        active = False

    elif 65 <= fee <= 100:
        print("$10 please!")
        active = False

    #convert negative numbers or letters into strings as to not cause a ValueError $ restart the while loop
    else:
        fee = str(fee)
        print("That's not your real age mate")
        continue
      
except ValueError:
  print('Please type only numbers. Letters will not be allowed.')

If you use value-error exception it will be useful to send error message like: "Please type only positive numbers. Negative numbers and letters will not be allowed. So that people understand".

And if you want to continue loop after exception then put it in a function like this:-

def once_again():
  try:
   active = True
   while active:
      print("How old are you?")
      fee = int(input())

      #Checks age of user to determine the price of a movie ticket
      if 0 <= fee <= 3:
        print("You're free mate")
        active = False

      elif 4 <= fee <= 12:
        print("$10 please!")
        active = False

      elif 13 <= fee <= 64:
        print("$15 please!")
        active = False

      elif 65 <= fee <= 100:
        print("$10 please!")
        active = False

      #convert negative numbers or letters into strings as to not cause a ValueError $ restart the while loop
      else:
        fee = str(fee)
        print("That's not your real age mate")
        continue
      
  except ValueError:
    print('Please type only positive numbers. Negative numbers and letters will not be allowed.')
    once_again()
    
once_again()

Output:-

there's a slight flaw in this logic in that a negative number will not raise an exception, so stating that negatives are not allowed in the `except` statement is not technically accurate. — chitown88, Jun 09 '21 at 10:06
This also does not continue the loop if a string is inputted. — realFishSam, Jun 09 '21 at 10:06
Please check my edited answer, now if you put it in function it works. Code given in edited answer — Dr. Strange Codes, Jun 09 '21 at 10:14

score 0 · Answer 2 · answered Jun 09 '21 at 10:02

Leave as string and only convert to an int by using .isdigit() to check if it's a digit

active = True

while active:
    print("How old are you?")
    fee = input()
    
    if not fee.isdigit():
        print("That's not your real age mate")
        continue
        
    fee = int(fee)

    #Checks age of user to determine the price of a movie ticket
    if 0 <= fee <= 3:
        print("You're free mate")
        active = False

    elif 4 <= fee <= 12:
        print("$10 please!")
        active = False

    elif 13 <= fee <= 64:
        print("$15 please!")
        active = False

    elif 65 <= fee <= 100:
        print("$10 please!")
        active = False

    #convert negative numbers or letters into strings as to not cause a ValueError $ restart the while loop
    else:
        print("That's not your real age mate")
        continue

integer input to string in else statement (Python)

2 Answers2