用函数实现if...elif...else

if n == 0:
    print('You typed zero.\n')
elif n == 1:
    print('You are in top.\n')
elif n == 2:
    print('n is an even number.\n')
else:
    print('Only single=digit number are allowed.\n')

可以用下面的跳转来实现

def f(n):
    return {
        0:'You typed zero.\n',
        1:'You are in top.\n',
        2:'n is an even number.\n'
    }.get(n, 'Only single=digit number are allowed.\n')