How to fix "During handling of the above exception, another exception occurred: "

Question

How do i fix this error, whenever i enter data that should cause an exception more than once the program crashes. Here is my code and what it outputs, it should keep repeating until correct data is entered.

code

flag=False

while flag==False:
    try:
        number=int(input("Enter number of books: "))
    except ValueError:
        print("Please enter number of books as a positive whole number ")
        number=int(input("Enter number of books: "))
    else:
        flag=True

errors

Traceback (most recent call last):
  File "C:\Users\Alex\OneDrive\Documents\ComputerScience\Intro2.py", line 5, in <module>
    number=int(input("Enter number of books: "))
ValueError: invalid literal for int() with base 10: '3.3'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Users\Alex\OneDrive\Documents\ComputerScience\Intro2.py", line 8, in <module>
number=int(input("Enter number of books: "))

ValueError: invalid literal for int() with base 10: '3.4'

To avoid that _specific_ error, don't raise another exception inside an `except` — tripleee, Sep 22 '22 at 19:31
@tripleee yes but how do i prevent it from crashing if a user raises an exception in the except? — pleasehelp, Sep 22 '22 at 19:35
Welcome to StackOverflow please post text, not images of text as it makes it easier for people to see and copy to evaluate. — Dan-Dev, Sep 22 '22 at 19:45
[Please do not upload images of code/data/errors when asking a question.](//meta.stackoverflow.com/q/285551) — buran, Sep 23 '22 at 03:21

Dan-Dev · Accepted Answer · 2022-09-22T22:58:03.820

1

Try this it evaluates if your string is a digit, then breaks out of the look. Exception handling is expensive in computing terms and should be avoided where possible

while True:
    no_of_books = input("enter number of books")
    if no_of_books.isdigit():
        break

The reason your code didn't keep repeating was that it thew an exception on line 5 which was wrapped in the try block then in the except block it threw another exception on line 8 which was not wrapped in a try block so it terminated

Updated in response to comment, simply cast your string to an int like this then use int_number_of_books as the int

while True:
    no_of_books = input("enter number of books")
    if no_of_books.isdigit():
        int_number_of_books = int(no_of_books)
        break
if int_number_of_books > 0:
    # your code here

edited Sep 22 '22 at 22:58

answered Sep 22 '22 at 19:47

Dan-Dev

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This doesnt seem to ensure that no_of_books is an integer as later on it refers to it as a string still. Here is error message : Traceback (most recent call last): File "C:\Users\Alex\OneDrive\Documents\ComputerScience\Intro2.py", line 7, in while number <= 0: TypeError: '<=' not supported between instances of 'str' and 'int' – pleasehelp Sep 22 '22 at 19:54
I need to ensure that the value is an integer and does not contain decimals or negatives – pleasehelp Sep 22 '22 at 19:59
See https://docs.python.org/3/library/stdtypes.html#str.isdigit of course you can use `if no_of_books.isdigit() and int(no_of_books) > 0:` to ensure that the value is a positive integer and does not contain decimals – Dan-Dev Sep 22 '22 at 22:57

How to fix "During handling of the above exception, another exception occurred: "

1 Answers1