如何使try函数仅打印我的消息一次

Question

I've tried using the try() function, but when i try: and then type print() it just prints the message non-stop. how do i make it only print once?

def inputInt(minv, maxv, message):
    res = int(input(message))
    while (res > minv) and (res < maxv):
        try:
            print("Good job.")
        except:
            print("Invalid input")

Answer 1

Have you tried with break ?

Take a look at this and this to get more clarification, but if you want that at the one time the try jumps to the except, it should print it once only, break is the thing.

I must say this loop will go on forever as you are not changing res . Even if it goes in the try or in the except .

Answer 2

The code that could raise an exception should be in the try . The input should be inside the while . Catch expected exceptions in case an unexpected exception occurs. A naked except is bad practice and can hide errors.

Here's a suggested implementation:

def inputInt(minv, maxv, message):
    while True: # Loop until break
        try:
            res = int(input(message)) # Could raise ValueError if input is not an integer.
            if minv <= res <= maxv:   # if res is valid,
                break                 #    exit while loop
        except ValueError:            # Ignore ValueError exceptions
            pass
        print("Invalid input")        # if didn't break, input or res was invalid.
    return res                        # Once while exits, res is good

x = inputInt(5,10,"enter number between 5 and 10: ")