python3 中的写法：
try:pass
except Exception as e:pass

num1 = input("num1:")
num2 = input("num2:")try:num1 = int(num1)num2 = int(num2)result = num1 + num2
except Exception as e:print ("出现异常，不是数字，信息如下") #定义异常处理的信息print (e) #打印错误信息输出：num1:chen
num2:2
出现异常，不是数字，信息如下
invalid literal for int() with base 10: 'chen'

 1 ArithmeticError
 2 AssertionError
 3 AttributeError
 4 BaseException
 5 BufferError
 6 BytesWarning
 7 DeprecationWarning
 8 EnvironmentError
 9 EOFError
10 Exception
11 FloatingPointError
12 FutureWarning
13 GeneratorExit
14 ImportError
15 ImportWarning
16 IndentationError
17 IndexError
18 IOError
19 KeyboardInterrupt
20 KeyError
21 LookupError
22 MemoryError
23 NameError
24 NotImplementedError
25 OSError
26 OverflowError
27 PendingDeprecationWarning
28 ReferenceError
29 RuntimeError
30 RuntimeWarning
31 StandardError
32 StopIteration
33 SyntaxError
34 SyntaxWarning
35 SystemError
36 SystemExit
37 TabError
38 TypeError
39 UnboundLocalError
40 UnicodeDecodeError
41 UnicodeEncodeError
42 UnicodeError
43 UnicodeTranslateError
44 UnicodeWarning
45 UserWarning
46 ValueError
47 Warning
48 ZeroDivisionError

异常种类1

AttributeError     试图访问一个对象没有的树形，比如foo.x，但是foo没有属性x
IOError              输入/输出异常；基本上是无法打开文件
ImportError        无法引入模块或包；基本上是路径问题或名称错误
IndentationError 语法错误（的子类） ；代码没有正确对齐
IndexError         下标索引超出序列边界，比如当x只有三个元素，却试图访问x[5]
KeyError            试图访问字典里不存在的键
KeyboardInterrupt   Ctrl+C被按下
NameError         使用一个还未被赋予对象的变量
SyntaxError        Python代码非法，代码不能编译
TypeError          传入对象类型与要求的不符合
UnboundLocalError   试图访问一个还未被设置的局部变量，基本上是由于另有一个同名的全局变量，
导致你以为正在访问它
ValueError      传入一个调用者不期望的值，即使值的类型是正确的

1 dic = ["chen","chen123"]
2 try:
3     dic[3]
4 except IndexError as e:
5     print("没有这大的值")
6     print(e)
7 输出：
8 没有这大的值
9 list index out of range

举例：IndexError

1 dic = {"chen":"chen123"}
2 try:
3     dic["qing"]
4 except KeyError as e:
5     print("没有这个key")
6     print(e)
7 输出：
8 没有这个key
9 'qing'

举例:KeyError

1 s1 = "chen"
2 try:
3     int(s1)
4 except ValueError as e:
5     print ("类型错误")
6     print(e)
7 输出：
8 类型错误
9 invalid literal for int() with base 10: 'chen'

举例：ValuesError

s1 = "chen"
try:int(s1)
except ValueError as e:print ("类型错误")print(e)

s1 = "chen"
try:int(s1)
except IndexError as e:print (e)
except KeyError as e:print (e)
except ValueError as e:print (e)

s1 = "chen"
try:int(s1)
except Exception as e:print ("类型错误")print(e)

s1 = 'chen'
try:int(s1)
except KeyError as e:print ('键错误')
except IndexError as e:print ('索引错误')
except Exception as e:print ('错误')

try:# 主代码块pass
except KeyError as e:# 异常时，执行该块pass
else:# 主代码块执行完，执行该块pass
finally:# 无论异常与否，最终执行该块pass

s1 = 'chen'
try:#主代码块int(s1)
except KeyError as e:#异常时，执行该模块print ('键错误')else:#主代码模块执行完，执行该块print ('索引错误')finally:#无论异常与否，最终执行该块print ('错误')输出：Traceback (most recent call last):File "/Users/mac/PycharmProjects/untitled2/51CTO/6day/异常处理.py", line 3, in <module>int(s1)
ValueError: invalid literal for int() with base 10: 'chen'
错误

try:raise Exception('错误了。。。')
except Exception as e:print (e)

1、当类型正确的情况下，自动触发 rasie
s1 = "123"
try:s1 = int(s1)raise Exception("类型正常。。")
except Exception as e:print(e)输出：
类型正常。。2、当类型不正确的情况下，直接执行Exception 捕获异常
s1 = "123"
s1 = "chen"
try:s1 = int(s1)raise Exception("类型正常。。")
except Exception as e:print(e)
输出：
invalid literal for int() with base 10: 'chen'

class ChenException(Exception):def __init__(self, msg):self.message = msgdef __str__(self):return self.messagetry:raise ChenException('我的异常') #调用了对象
except ChenException as e:print(e)
输出：
我的异常

1、assert 条件
assert 1 == 1
assert 1 == 2
输出：
Traceback (most recent call last):File "/Users/mac/PycharmProjects/untitled2/51CTO/6day/异常处理.py", line 2, in <module>assert 1 == 2
AssertionError===============================================
2、捕获异常
try:assert 1 == 1assert 1 == 2
except AssertionError as e:print(e)
except Exception as e:print(e)没有任何的错误输出，这个应该是用来忽略错误的时候。