Test if an Exception is Raised when Taking User Input in a Function

What will you learn?

In this tutorial, you will master the art of handling exceptions within Python functions that accept user input. By learning how to gracefully manage unexpected inputs from users, you’ll be equipped to ensure your programs remain robust and reliable even in the face of errors.

Introduction to the Problem and Solution

Encountering unexpected inputs from users is a common challenge faced by developers. However, by incorporating exception handling mechanisms into our Python functions, we can proactively address potential errors that may arise during program execution. This approach not only prevents abrupt crashes but also enables us to provide informative error messages or implement alternative actions when needed.

When it comes to validating user input, anticipating various scenarios that could trigger exceptions is key. Through the use of try-except blocks, we can effectively capture these exceptions and respond accordingly within our codebase. This practice significantly enhances the overall resilience and dependability of our software.


def get_user_input():
        user_input = int(input("Please enter a number: "))
        return user_input
    except ValueError as e:
        print("Error:", e)
        return None

# Main program flow
user_number = get_user_input()
if user_number is not None:
    print("User input is:", user_number)

# Copyright PHD

– Define a function get_user_input() that attempts to convert user input into an integer. – If a ValueError occurs during conversion (e.g., invalid integer input), catch the exception, display an error message, and return None. – In the main program flow, call get_user_input() and store the returned value in user_number. – If a valid number was entered (i.e., user_number is not None), display it; otherwise, take no further action.

    How do exceptions help in handling errors?

    Exceptions aid in detecting errors or exceptional conditions at runtime and offer mechanisms for managing them gracefully without crashing the program.

    What does the keyword “except” signify?

    The keyword “except” marks the beginning of a block where specific types of exceptions are caught and handled within Python code.

    Can multiple except blocks be used for different types of exceptions?

    Yes, multiple except blocks can be employed to catch distinct types of exceptions based on specific error scenarios encountered during execution.

    Is it necessary to always handle exceptions explicitly?

    While explicit exception handling boosts code robustness, there are situations where allowing unhandled exceptions to propagate upwards may be suitable depending on application needs.

    What happens if an exception occurs but isn’t caught by any handler?

    If an uncaught exception arises within your codebase, Python’s default behavior includes displaying an error message along with traceback information before abruptly exiting.

    How does using try-except improve code readability compared to traditional error checking methods?

    By encapsulating potentially error-prone operations inside try-except constructs, developers can segregate normal logic from exceptional case handling effectively improving code maintainability and clarity.


    Mastering exception handling when dealing with user input in Python functions is essential for constructing dependable applications. By integrating proper validation techniques alongside strategic use of try-except blocks, you can elevate both functionality and resilience within your programs. Remember – adept error-handling paves the way for superior software quality!

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