冰冻三尺非一日之寒--面向对象

1 class Foo:
2  
3     def __str__(self):
4         return ‘tom‘
5  
6  
7 obj = Foo()
8 print obj
9 # 输出：tom

 1 class Foo(object):
 2  
 3     def __getitem__(self, key):
 4         print(‘__getitem__‘,key)
 5  
 6     def __setitem__(self, key, value):
 7         print(‘__setitem__‘,key,value)
 8  
 9     def __delitem__(self, key):
10         print(‘__delitem__‘,key)
11  
12  
13 obj = Foo()
14  
15 result = obj[‘k1‘]      # 自动触发执行 __getitem__
16 obj[‘k2‘] = ‘alex‘   # 自动触发执行 __setitem__
17 del obj[‘k1‘]    

1 class Foo(object):
2  
3  
4     def __init__(self,name):
5         self.name = name
6  
7  
8 f = Foo("alex")

 1 def func(self):
 2     print("hello %s"%self.name)
 3 
 4 def __init__(self,name,age):
 5     self.name = name
 6     self.age = age
 7 Foo = type(‘Foo‘,(object,),{‘func‘:func,‘__init__‘:__init__})
 8 
 9 f = Foo("jack",22)
10 f.func()

 1 #_*_coding:utf-8_*_
 2 __author__ = ‘Alex Li‘
 3  
 4  
 5 class MyType(type):
 6  
 7     def __init__(self, what, bases=None, dict=None):
 8         print("--MyType init---")
 9         super(MyType, self).__init__(what, bases, dict)
10  
11     def __call__(self, *args, **kwargs):
12         print("--MyType call---")
13         obj = self.__new__(self, *args, **kwargs)
14  
15         self.__init__(obj, *args, **kwargs)
16  
17  
18 class Foo(object):
19  
20     __metaclass__ = MyType
21  
22     def __init__(self, name):
23         self.name = name
24         print("Foo ---init__")
25  
26     def __new__(cls, *args, **kwargs):
27         print("Foo --new--")
28         return object.__new__(cls)
29  
30  
31 # 第一阶段：解释器从上到下执行代码创建Foo类
32 # 第二阶段：通过Foo类创建obj对象
33 obj = Foo("Alex")

1 def getattr(object, name, default=None): # known special case of getattr
2     """
3     getattr(object, name[, default]) -> value
4     
5     Get a named attribute from an object; getattr(x, ‘y‘) is equivalent to x.y.
6     When a default argument is given, it is returned when the attribute doesn‘t
7     exist; without it, an exception is raised in that case.
8     """
9     pass

1 判断object中有没有一个name字符串对应的方法或属性

1 def setattr(x, y, v): # real signature unknown; restored from __doc__
2     """
3     Sets the named attribute on the given object to the specified value.
4     
5     setattr(x, ‘y‘, v) is equivalent to ``x.y = v‘‘

1 def delattr(x, y): # real signature unknown; restored from __doc__
2     """
3     Deletes the named attribute from the given object.
4     
5     delattr(x, ‘y‘) is equivalent to ``del x.y‘‘
6     """

 1 class Foo(object):
 2  
 3     def __init__(self):
 4         self.name = ‘wupeiqi‘
 5  
 6     def func(self):
 7         return ‘func‘
 8  
 9 obj = Foo()
10  
11 # #### 检查是否含有成员 ####
12 hasattr(obj, ‘name‘)
13 hasattr(obj, ‘func‘)
14  
15 # #### 获取成员 ####
16 getattr(obj, ‘name‘)
17 getattr(obj, ‘func‘)
18  
19 # #### 设置成员 ####
20 setattr(obj, ‘age‘, 18)
21 setattr(obj, ‘show‘, lambda num: num + 1)
22  
23 # #### 删除成员 ####
24 delattr(obj, ‘name‘)
25 delattr(obj, ‘func‘)

1 import importlib
2  
3 __import__(‘import_lib.metaclass‘) #这是解释器自己内部用的
4 #importlib.import_module(‘import_lib.metaclass‘) #与上面这句效果一样，官方建议用这个

 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

ArithmeticError
AssertionError
AttributeError
BaseException
BufferError
BytesWarning
DeprecationWarning
EnvironmentError
EOFError
Exception
FloatingPointError
FutureWarning
GeneratorExit
ImportError
ImportWarning
IndentationError
IndexError
IOError
KeyboardInterrupt
KeyError
LookupError
MemoryError
NameError
NotImplementedError
OSError
OverflowError
PendingDeprecationWarning
ReferenceError
RuntimeError
RuntimeWarning
StandardError
StopIteration
SyntaxError
SyntaxWarning
SystemError
SystemExit
TabError
TypeError
UnboundLocalError
UnicodeDecodeError
UnicodeEncodeError
UnicodeError
UnicodeTranslateError
UnicodeWarning
UserWarning
ValueError
Warning
ZeroDivisionError

更多异常

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

dic = {‘k1‘:‘v1‘}
try:
    dic[‘k20‘]
except KeyError, e:
    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 socket
 5 
 6 ip_port = (‘127.0.0.1‘,9999)
 7 
 8 sk = socket.socket()
 9 sk.bind(ip_port)
10 sk.listen(5)
11 
12 while True:
13     print ‘server waiting...‘
14     conn,addr = sk.accept()
15 
16     client_data = conn.recv(1024)
17     print client_data
18     conn.sendall(‘不要回答,不要回答,不要回答‘)
19 
20     conn.close()

 1 #!/usr/bin/env python
 2 # -*- coding:utf-8 -*-
 3 import socket
 4 ip_port = (‘127.0.0.1‘,9999)
 5 
 6 sk = socket.socket()
 7 sk.connect(ip_port)
 8 
 9 sk.sendall(‘请求占领地球‘)
10 
11 server_reply = sk.recv(1024)
12 print server_reply
13 
14 sk.close()
15 
16 复制代码