How to create a exception for a while loop to repeat a input-CodePudding

I am trying to get this bit of code to work to validate the following input. I want to only accept inputs 1,2,or 3. Here is what I have so far:

number = int(input('Enter a number:'))
done = False
while not done:
    try:
        if number < 3:
            done = True
    except:
        number = input("Please enter a valid number:")

The expected out put that I want if the input to loop until I get either 1,2, or 3. Right now it won't do anything to when I input something greater than three. I want to use this number as an input to another function. Any help would be great of if you need more information please let me know!

CodePudding user response：

Try this

number = int(input('Enter a number:'))
done = False
while not done:
    if number <= 3:
        done = True
    else:
        number = int(input("Please enter a valid number:"))

except block only run when there is an error in try block code.

Use if-else statement.

You can use this one too.

number = int(input('Enter a number:'))
done = False
while number>3:
    number = int(input('Please enter a valid number:'))

CodePudding user response：

Walrus operator (:=) comes in handy to validate input while its value greater than 3 or lesser/equals than 0 and only accept 1, 2, or 3.

while not 3 >= (number := int(input('Enter a number:'))) > 0:
    print('Please enter a valid number')

or:

while (number := int(input('Enter a number:'))) not in (1,2,3):
    print('Please enter a valid number')

Output:

# Enter a number:0
# Please enter a valid number
# Enter a number:-1
# Please enter a valid number
# Enter a number:4
# Please enter a valid number
# Enter a number:3

Process finished with exit code 0