一篇文章带你了解python异常基础

>>> if True
SyntaxError: invalid syntax
>>> 

>>> def print_D(dic):
	i=0
	len1=len(dic)
	while i < len1:
		print(dic.popitem())    #随机删除并返回一个元素
		i+=1
		
>>> print_D({1:'a',2:'b'})
(2, 'b')
(1, 'a')

>>> print_D([1,2,3,4])
Traceback (most recent call last):
  File "<pyshell#11>", line 1, in <module>
    print_D([1,2,3,4])
  File "<pyshell#9>", line 5, in print_D
    print(dic.popitem())
AttributeError: 'list' object has no attribute 'popitem'

try:
	代码模块1
except:
	代码模块2

>>> def print_D(dic):
	i=0
	try:
		len1=len(dic)
		while i < len1:
			print(dic.popitem())
			i+=1
	except:
		print('传递值类型出错，必须为字典类型！')
		
>>> print_D({1:'a',2:'b'})
(2, 'b')
(1, 'a')
>>> print_D([1,2,3,4])
传递值类型出错，必须为字典类型！        #出错后的正确提示信息

try:
	代码模块1
except:
	代码模块2
finally:
	代码模块3

>>> try:
	1/0
except:
	print('除数不能为0')
finally:
	print('出现执行结束')
>>> 

>>> try:
	1/2
except:
	print('出书不能为0')
finally:
	print('出现运行结束')
>>> 

import sys
try:
	1/0
except:
	print('除数不能为0')
	sys.exit()
finally:
	print('程序执行结束')
print('我能执行码？')
>>> 

try:
    print("正常代码")
except Exception as e:
    print("将不会输出这句话")
else:
    print("这句话将被输出")
print('-'*30)
try:
    print(1/0)
except Exception as e:
    print("进入异常处理")
else:
    print("不会输出")

>>> 

try:
    print("没有异常")
except Exception as e:
    print("不会输出！")
else:
    print("进入else")
finally:
    print("必须输出！")
print('-'*30)
try:
    print(1/0)
except Exception as e:
    print("引发异常")
else:
    print("不会进入else")
finally:
    print("必须输出！")
>>>

raise [Exception]

>>> raise
Traceback (most recent call last):
  File "<pyshell#52>", line 1, in <module>
    raise
RuntimeError: No active exception to reraise
>>> 

>>> i='1'
>>> if type(i)!=int:
	raise TypeError('i类型出错！')
Traceback (most recent call last):
  File "<pyshell#57>", line 2, in <module>
    raise TypeError('i类型出错！')
TypeError: i类型出错！
>>>