第一种：try except  抛出异常结束程序运行

def collatz(number):
    try:
        number = int(number)
        if number % 2 == 0:
            return number // 2
        elif number % 2 == 1:
            return 3 * number + 1
    except ValueError:
        return '类型错误'

for i in range(1,7):
    num = input()
    print(collatz(num))
    print('你已经输入了{0}次，还剩{1}次！'.format(i,7-i))

第二中：try  except finally 抛出异常后继续执行

def collatz(number):
    try:
        number = int(number)
        if number % 2 == 0:
            return number // 2
        elif number % 2 == 1:
            return 3 * number + 1
    except ValueError:
       global re
       re = '类型错误'
       print(re)
       return ''
    finally:
        print('我是在抛出{0}异常后，继续运行的程序块！'.format(re))

for i in range(1,7):
    num = input()
    print(collatz(num))
    print('你已经输入了{0}次，还剩{1}次！'.format(i,7-i))