How do I validate user input while catching other data types?-CodePudding

Trying to validate user input in my program.

 playerChoice = int(input("Enter your choice: "))
    

while playerChoice != 1 and playerChoice != 2 and playerChoice != 3 and playerChoice !=4:
    print("Please make a valid selection from the menu.")
    playerChoice = int(input("Enter your choice: "))

This works great as long as the input is an integer (the problem statement specifically states the input is an integer). However, if I enter 1.5 or xyz, I get an unhandled ValueError exception.

So I changed it:

try:
    playerChoice = int(input("Enter your choice: "))
    
    while playerChoice not in(1, 2, 3, 4):
        print("Please make a valid selection from the menu.")
        playerChoice = int(input("Enter your choice: "))
                   
except ValueError:
    print("Please enter a number.")
    playerChoice = int(input("Enter your choice: "))

which also works great...once. I know the solution here is simple but I can't figure out how to get the code into a loop that will handle other data types. What am I missing?

Sorry for asking such a dumb question.

CodePudding user response：

Put the try/except inside your loop:

while True:
    try:
        playerChoice = int(input("Enter your choice: "))
        if playerChoice not in (1, 2, 3, 4):
            print("Please make a valid selection from the menu.")
        else:
            break
    except ValueError:
        print("Please enter a number.")

CodePudding user response：

Put a while loop around the whole thing.

while True:
    try:
        playerChoice = int(input("Enter your choice: "))
        
        if playerChoice in(1, 2, 3, 4):
            break
            
        print("Please make a valid selection from the menu.")
                       
    except ValueError:
        print("Please enter a number.")

Notice that by putting the input() call inside the main loop, you only have to write it once, rather than repeating it after all the validation checks.

CodePudding user response：

It is because you put the try ... except clause outside of the loop, while you want it to be inside of it.

playerChoice = None
while not playerChoice:
    try:
        playerChoice = int(input("Enter your choice: "))
        if playerChoice not in(1, 2, 3, 4) :
            print("Please make a valid selection from the menu.")
            playerChoice = None
    except ValueError:
        print("Please enter a number.")