What is Input Validation?

Input validation is the process of ensuring that the data entered by the user meets certain criteria before it is processed by the program. This is important to prevent errors and ensure that the program behaves as expected.

Input Validation Techniques

There are many ways to validate user input in Python, but one common technique is to use a while loop to repeatedly ask the user for input until they provide valid data.

Here’s an example of how to validate that the user enters a positive integer:

while True: # create an infinite loop
    user_input = input("Please enter a positive integer: ") # ask the user for input and store it in the variable user_input
    if user_input.isdigit() and int(user_input) > 0:   # check if the input is a digit and greater than 0
        print("Thank you for entering a valid positive integer!")
        break # exit the loop if the input is valid
    else:
        print("Invalid input. Please try again.") # tell the user their input was invalid and ask them to try again