异常是什么
python使用异常对象来表示异常状态，并在遇到错误时引发异常，异常对象未被处理时，程序将终止并显示一条错误信息。
让事情沿你指定的轨道出错
raise语句
In
[59]: raise Exception
---------------------------------------------------------------------------
Exception Traceback
(most recent call last
)
<ipython
-input-59-2aee0157c87b> in <module
>
----> 1 raise Exception
Exception
:
In
[60]: raise Exception
('NullPointException')
---------------------------------------------------------------------------
Exception Traceback
(most recent call last
)
<ipython
-input-60-b8fd742899da
> in <module
>
----> 1 raise Exception
('NullPointException')
Exception
: NullPointException
自定义异常类
class SomeCustomException(Exception
): pass
class MyExceptionClass(Exception
):
def __init__(self
, code
, msg
):
self
.code
= code
self
.msg
= msg
super(MyExceptionClass
, self
).__init__
()
@
staticmethod
def test():
content
= input("input Str:")
if len(content
) > 5:
raise MyExceptionClass
('1001', '长度小于5')
else:
print(content
)
if __name__
== '__main__':
MyExceptionClass
.test
()
捕获异常
class TryDemo(object):
def test(self
):
a
= int(input("输入第一个数："))
print('\n')
b
= int(input("输入第二个数："))
print(a
/ b
)
if __name__
== '__main__':
tryDemo
= TryDemo
()
tryDemo
.test
()
输入第一个数：
10
输入第二个数：
0
Traceback
(most recent call last
):
File
"D:/pythonProject/demo1124/com/example/demo1214/TryDemo.py", line
12, in <module
>
tryDemo
.test
()
File
"D:/pythonProject/demo1124/com/example/demo1214/TryDemo.py", line
7, in test
print(a
/ b
)
ZeroDivisionError
: division by zero
捕获异常
def test():
a
= int(input("输入第一个数："))
b
= int(input("输入第二个数："))
try:
print(a
/ b
)
except ZeroDivisionError
:
print("第二个数不能为0")
class TryDemo(object):
pass
if __name__
== '__main__':
tryDemo
= TryDemo
()
test
()
输入第一个数：
10
输入第二个数：
0
第二个数不能为
0
不用提供参数
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