python学习（11）- 捕获异常

刺骨的言语ヽ痛彻心扉 2022-12-27 15:23 185阅读 0赞

Python学习（10）- 文件操作

[https://blog.csdn.net/caoyan0829/article/details/110530723][https_blog.csdn.net_caoyan0829_article_details_110530723]

捕获异常：

# 捕获具体异常 一个
    try:
        open('11.txt', 'r')  # 没有10.txt文件，报错FileNotFoundError
    except FileNotFoundError:
        print('出错了，没有该文件')
    else:
        print('没有问题')
    finally:
        print('对错都会执行')
    """
    
    异常	            描述
    NameError	        尝试访问一个没有申明的变量
    ZeroDivisionError	除数为0
    SyntaxError	        语法错误
    IndexError	        索引超出序列范围
    KeyError	        请求一个不存在的字典关键字
    IOError	            输入输出错误（比如你要读的文件不存在）
    AttributeError	    尝试访问未知的对象属性
    """
    
    
    # 捕获具体异常 多个
    try:
        print(1 / 0)  # 报错 ZeroDivisionError: division by zero
        open('10.txt', 'r')  # 没有10.txt文件，报错FileNotFoundError
    
    except (FileNotFoundError, ZeroDivisionError):
        print('报错了')
    
    
    #捕获所有错误
    try:
        print(1/0)
    except Exception as result:
        print('报错了--',result)
    else:
        print('没有异常执行')
    
    
    
    
    try:
        print('try...')
        r = 10 / 0
        print('result:', r)
    except ZeroDivisionError as e:
        print('except:', e)
    finally:
        print('finally...')
    print('END\n')
    
    
    #传递性
    print('测试开始')
    from functools import reduce
    
    def str2num(s):
        try:
            return int(s)
        except ValueError as result:
            print("出错了，",result)
            return float(s)
        # finally:
            # print('END')
    def calc(exp):
        ss = exp.split('+')
        ns = map(str2num, ss)
        return reduce(lambda acc, x: acc + x, ns)
    
    def main():
        # try:
            r = calc('100 + 200 + 345')
            print('100 + 200 + 345 =', r)
            r = calc('99 + 88 + 7.6')
            print('99 + 88 + 7.6 =', r)
        # except Exception as result:
        #     print("出错了，",result)
        # finally:
        #     print('END')
    main()
    
    
    #调用栈
    
    
    
    #自定义异常  输入老王就异常
    class MyException(Exception):
        def __init__(self,name):
            self.name = name
    
    def test():
        name = input('请输入名字')
        try:
            if name == '老王':
                #抛出   raise
                raise MyException(name)
        except MyException as item:
            print('出错了',item)
    test()
    
    
    #异常中抛出异常
    try:
        open('333.txt','r')
    except Exception as e:
        raise  #捕获到了，抛出去了

Python学习（12）- 模块与包

[https://blog.csdn.net/caoyan0829/article/details/111209604][https_blog.csdn.net_caoyan0829_article_details_111209604]

[https_blog.csdn.net_caoyan0829_article_details_110530723]: https://blog.csdn.net/caoyan0829/article/details/110530723
[https_blog.csdn.net_caoyan0829_article_details_111209604]: https://blog.csdn.net/caoyan0829/article/details/111209604