Python 3限制基数10输入值

Question

I am new to Python so not sure how best to structure this.

I have a user inputing a number stored as B.

The number can only be between 0-7.

If the user enters 8 we print an error message.

Sorry for the simplistic nature of the questio?

Thank you

Answer 1

You can input any base number up to base 36:

int(number, base)

Example:

>>> int("AZ14", 36)
511960

If you are talking about limiting the range of a base ten number, here's an example of that:

>>> the_clamps = lambda n, i, j: i if n < i else j if n > j else n
>>> for n in range(0, 10): print((the_clamps(n, 4, 8)))
... 
4
4
4
4
4
5
6
7
8
8
>>>

Amendment:

To generate and handle errors:

>>> def mayhem(n, i, j):
...     if n < i or n > j: raise Exception("Out of bounds: %i." % n)
...     else: return n
... 
>>> for n in range(10):
...     try: print((mayhem(n, 4, 8)))
...     except Exception as e: print((e))
... 
Out of bounds: 0.
Out of bounds: 1.
Out of bounds: 2.
Out of bounds: 3.
4
5
6
7
8
Out of bounds: 9.

Answer 2

Constantly asks user for input, until a valid answer is given ( break exits while True loop). ValueError is handled by the try since it can be raised if user gives something like 1.2 or hello . Note that input() assigns a string to user_answer .

(I am assuming you want an int not a float .)

user_answer = None
while True:    
    user_answer = input('Give a num from 0 to 7')

    try:
        if 0 <= int(user_answer) <=7:
            break
        else:
            print('Out of range.')
            continue

    except ValueError:
        print('Invalid answer, try again.')


print('Given number: {}'.format(user_answer))