python异常处理

Posted 2020-10-24 jason-lin

什么是异常

异常就是程序运行时发生错误的信号

错误分为两种

1、语法错误

pychram 能检查出来的错误

if 

def test:
pass

2、逻辑错误

pycharm 不能检查的错误

num = inpu(">>").strip()
int(num)

异常处理

ss = "hello"
# s = "10"
try:
    int(s)
except TypeError as e:
    print(e)
except KeyError as e:
    print(e)
except Exception as e:  # 万能异常
    print(e)
else:
    print("没有异常")
finally:
    print("有没有异常都要执行我")

自定义异常

class Myerror(Exception):
    pass
    
    
try:
    raise Myerror("hi")
except Myerror as e:
    print(e)

断言

assert 1 == 1
assert 1 == 2  # 触发AssertionError异常