How To Validate Input Using If And Else

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1 How to validate input using if and else

Problem Description:

I’ve to create a program that takes 2 random prime numbers between 10,000-20,000 and sum them together. I seem to have gotten this ok, but when I ask if the user wants to generate another set within a loop I cant seem to get the validation working. I wont include the code that figures out the prime number as that is working ok.

val_1 = random.choice(prime_list)
    val_2 = random.choice(prime_list)   
    print("This program will find 2 prime numbers in the specified range and sum themn")
    print(val_1, "is the first number and", val_2, "is the second numbern")
    print(val_1, "+", val_2, "=", val_1 + val_2)
    
    
    
    #PLAY AGAIN
    while True:
        reset = input("Would you like to generate 2 new numbers? Y/N ").lower()
        
        if reset == "y":
            val_1 = random.choice(prime_list)
            val_2 = random.choice(prime_list)  

            print(val_1, "is the first number and",val_2, "is the second numbern")
            print(val_1, "+", val_2, "=", val_1 + val_2)

            continue
        else:
            print("Goodbye") 
            quit()

Thanks for any help.

What I have tried is using if result != "y" or "n" and it just seems to then loop the question.

Solution – 1

If you write if result != "y" or "n":, it is interpreted the same as if (result != "y") or ("n"):. Because the non-empty string "n" evaluates to True, this if statement will always be true. Try something like:

while True:
    reset = input("Would you like to generate 2 new numbers? Y/N ").lower()
    if reset not in {"y", "n"}:
        print("Invalid input")
        continue
    # Process valid input here

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