Python之路【第五篇】：面向对象及相关

 1 while True:
 2     num1 = raw_input(‘num1:‘)
 3     num2 = raw_input(‘num2:‘)
 4     try:
 5         num1 = int(num1)
 6         num2 = int(num2)
 7         result = num1 + num2
 8     except Exception, e:
 9         print ‘出现异常，信息如下：‘
10         print e

 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
 2 IOError 输入/输出异常；基本上是无法打开文件
 3 ImportError 无法引入模块或包；基本上是路径问题或名称错误
 4 IndentationError 语法错误（的子类） ；代码没有正确对齐
 5 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]
 6 KeyError 试图访问字典里不存在的键
 7 KeyboardInterrupt Ctrl+C被按下
 8 NameError 使用一个还未被赋予对象的变量
 9 SyntaxError Python代码非法，代码不能编译(个人认为这是语法错误，写错了）
10 TypeError 传入对象类型与要求的不符合
11 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，
12 导致你以为正在访问它
13 ValueError 传入一个调用者不期望的值，即使值的类型是正确的
14 
15 常用异常

 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
49 
50 更多异常

1 dic = ["wupeiqi", ‘alex‘]
2 try:
3     dic[10]
4 except IndexError, e:
5     print e

1 dic = {‘k1‘:‘v1‘}
2 try:
3     dic[‘k20‘]
4 except KeyError, e:
5     print e

1 s1 = ‘hello‘
2 try:
3     int(s1)
4 except ValueError, e:
5     print e

 1 #!/usr/bin/env python
 2 # -*- coding:utf-8 -*-
 3 
 4 import sys
 5 
 6 
 7 def s1():
 8     print ‘s1‘
 9 
10 
11 def s2():
12     print ‘s2‘
13 
14 
15 this_module = sys.modules[__name__]
16 
17 hasattr(this_module, ‘s1‘)
18 getattr(this_module, ‘s2‘)
19 
20 反射当前模块成员

1 #!/usr/bin/env python
2 # -*- coding:utf-8 -*-
3 
4 def dev():
5     return ‘dev‘

 1 #!/usr/bin/env python
 2 #coding:utf-8
 3 from wsgiref.simple_server import make_server
 4 
 5 
 6 class DbHelper(object):
 7 
 8     def __init__(self):
 9         self.hostname = ‘1.1.1.1‘
10         self.port = 3306
11         self.password = ‘pwd‘
12         self.username = ‘root‘
13 
14     def fetch(self):
15         # 连接数据库
16         # 拼接sql语句
17         # 操作
18         return ‘fetch‘
19 
20     def create(self):
21         # 连接数据库
22         # 拼接sql语句
23         # 操作
24         return ‘create‘
25 
26     def remove(self):
27         # 连接数据库
28         # 拼接sql语句
29         # 操作
30         return ‘remove‘
31 
32     def modify(self):
33         # 连接数据库
34         # 拼接sql语句
35         # 操作
36         return ‘modify‘
37 
38 
39 class Handler(object):
40 
41     def index(self):
42         # 创建对象
43         db = DbHelper()
44         db.fetch()
45         return ‘index‘
46 
47     def news(self):
48         return ‘news‘
49 
50 
51 def RunServer(environ, start_response):
52     start_response(‘200 OK‘, [(‘Content-Type‘, ‘text/html‘)])
53     url = environ[‘PATH_INFO‘]
54     temp = url.split(‘/‘)[1]
55     obj = Handler()
56     is_exist = hasattr(obj, temp)
57     if is_exist:
58         func = getattr(obj, temp)
59         ret = func()
60         return ret
61     else:
62         return ‘404 not found‘
63 
64 if __name__ == ‘__main__‘:
65     httpd = make_server(‘‘, 8001, RunServer)
66     print "Serving HTTP on port 8001..."
67     httpd.serve_forever()
68 
69 Web应用程序实例

 1 #!/usr/bin/env python
 2 #coding:utf-8
 3 from wsgiref.simple_server import make_server
 4 
 5 # ########### 单例类定义 ###########
 6 class DbHelper(object):
 7 
 8     __instance = None
 9 
10     def __init__(self):
11         self.hostname = ‘1.1.1.1‘
12         self.port = 3306
13         self.password = ‘pwd‘
14         self.username = ‘root‘
15 
16     @staticmethod
17     def singleton():
18         if DbHelper.__instance:
19             return DbHelper.__instance
20         else:
21             DbHelper.__instance = DbHelper()
22             return DbHelper.__instance
23 
24     def fetch(self):
25         # 连接数据库
26         # 拼接sql语句
27         # 操作
28         pass
29 
30     def create(self):
31         # 连接数据库
32         # 拼接sql语句
33         # 操作
34         pass
35 
36     def remove(self):
37         # 连接数据库
38         # 拼接sql语句
39         # 操作
40         pass
41 
42     def modify(self):
43         # 连接数据库
44         # 拼接sql语句
45         # 操作
46         pass
47 
48 
49 class Handler(object):
50 
51     def index(self):
52         obj =  DbHelper.singleton()
53         print id(single)
54         obj.create()
55         return ‘index‘
56 
57     def news(self):
58         return ‘news‘
59 
60 
61 def RunServer(environ, start_response):
62     start_response(‘200 OK‘, [(‘Content-Type‘, ‘text/html‘)])
63     url = environ[‘PATH_INFO‘]
64     temp = url.split(‘/‘)[1]
65     obj = Handler()
66     is_exist = hasattr(obj, temp)
67     if is_exist:
68         func = getattr(obj, temp)
69         ret = func()
70         return ret
71     else:
72         return ‘404 not found‘
73 
74 if __name__ == ‘__main__‘:
75     httpd = make_server(‘‘, 8001, RunServer)
76     print "Serving HTTP on port 8001..."
77     httpd.serve_forever()
78 
79 Web应用实例-单例模式