Input Validation in Python

Input Validation in Python – Python Program to show number input validation.

Write a program that takes a number as input and handles any exceptions that may occur if the user enters a non-numeric value.

Write a program that takes a number as input and handles any exceptions that may occur if the user enters a non-numeric value.

Source Code

while True:
    try:
        user_input = input("Enter a number: ")
        number = float(user_input)
        # If the input is successfully converted to a float, break out of the loop.
        break
    except ValueError:
        print("Invalid input. Please enter a valid numeric value.")

print("You entered a valid number:", number)

Output

Enter a number: hello
Invalid input. Please enter a valid numeric value.
Enter a number: @3
Invalid input. Please enter a valid numeric value.
Enter a number: ***
Invalid input. Please enter a valid numeric value.
Enter a number: open
Invalid input. Please enter a valid numeric value.
Enter a number: 130
You entered a valid number: 130.0

In this program:

1. We use a while loop to repeatedly prompt the user for input until they provide a valid numeric value.
2. Inside the try block, we attempt to convert the user’s input to a floating-point number using float(user_input).
3. If the conversion is successful, the input is considered valid, and we break out of the loop.
4. If the conversion raises a ValueError exception (i.e., the user entered a non-numeric value), we catch the exception in the except block, display an error message, and continue the loop, prompting the user for input again.

Once the user enters a valid number, the program will display the number they entered.