python3 Exception自定义异常类

1.自定义异常类
2.抛出异常
3.捕获异常

1.
class Error(Exception):
    def __init__(self,length,min_length):
        self.length = length
        self.min_len = min_length
    # 异常描述信息
    def __str__(self):
        return f'你输入的长度是{self.length},不能少于{self.min_len}'
def main():
    try:
        con = input('请输入密码: ')
        if len(con)<3:
            # 抛出异常
            2.
            raise Error(len(con),3)
    # 捕获异常
    3.
    except Exception as result:
        print(result)
    else:
        print("输入完成")
main()