python programming examples advanced

written in generator style:1 defGenerator_func ():2Wwwlog = open ("Access-log")3 #returns a Generator object using the generator expression (Generator expression)4Bytecolumn = (Line.rsplit (None, 1) [1] forLineinchWwwlog)5bytes = (int (x) forXinchBytecolumnifX! ="-")6 7 #The final step is calculated8 Print " Total", sum (bytes)As you can see, with generator, you can write less code and have a completely different programming style than no

is an internal scope def F1 (): ... Print # This is F2 () is scoped def F2 (): ... ' Eric ' ... >>> F2 () AlexPython is a scoped chain (small knowledge point four)>>> name ='Alex'# This is F1 () is a scope, it is an internal scope>>>defF1 (): ...Print(name) ...#this is F2 () is a scope>>>defF2 (): ... name='Eric'... returnF1 ...>>> ret =F2 ()>>> ret ()#this is equivalent to running F1 ()AlexPython is a scoped chain (small knowledge point five) for Loop, then add 1 to ea

Variables can point to functions Parameters of a function can receive variables A function can receive another function as a parameter Functions that can receive functions as arguments are higher-order functions. Example: Receiving ABS function Define a function to receive x,y,f three parameters where x, Y is a number, F is a function >>>def add(x,y,f):...return f(x)+f(y)...>>> add(-5,9,abs)14The code above, as defined by the function,

= ' [email protected] ', password= ' my-pwd ')U.save ()The output is as follows:Found Model:userFound Mapping:email ==>Found Mapping:password ==>Found Mapping:id ==>Found Mapping:name ==>Sql:insert into User (password,email,username,id) VALUES (?,?,?,?)ARGS: [' my-pwd ', ' [email protected] ', ' Michael ', 12345]As you can see,the Save () method has printed out the executable SQL statement, as well as the parameter list, so that you can actually connect to the database and execute the SQL statem

require the interface to be added as a core feature of Python, and the current people who want to use the interface are now forced to use the Zope interface or PyprotocolsPreviously, Guido refused to add interfaces to Python because they were not suitable for Python's dynamic duck-typing features, but the interface system proved their value in some cases, so python3000 would introduce a knownOption type an

Install Ipython 1.3 Installing Setuptools 28 Setuptools: Package management system, publish Python application, equivalent to Debian in the apt; PyPI (Python package Index): Centralized warehouse; is not the standard library, but also to install; 1.3.1 Installation with Easyinstall Easyinstall seems to have been installed; "D:\Python27\Scripts\easy_install.exe" See if there are any setuptools installed;

parentheses and the allowed binding property inherited from the parent class, (there are two types, the parent has slots statements and no slots statements):　　　　The parent class does not have a slots statement, and although the subclass has restrictions, it can still bind other types:　　　　The parent class has the slots statement above already has, does not demonstrate;3. Multiple Inheritance:1) Java only allows single re-inheritance, Pyhon allows multiple inheritance, with mixin design implement

) print (' Exc_tb ', EXC_TB) Returntruewithfoo () asobj: #res =foo (). __enter__ () #obj =res print (' Withfoo Self code block ', obj) raisenameerror (' name not defined ') print (' ************************************ ') print ('------> ') The three parameters in __exit__ () represent the exception type, outliers and traceability information, and the code block in the WITH statement has an exception, and the code after the with cannot be executed, but the code outside the With statement blo

Because of the time relationship, Python advanced programming is not on this side to learn, if the need for friends can see the following network disk for download# #-*-Coding:utf-8-*-# # python:2.x# __author__ = ' Administrator '#使用API#跟踪冗长#创建代码库时, the most common error is the API verbose (API verbosity), when a featu

method with the same name as the Polymorphic method.5.3 Polymorphism of Dynamic languagesA dynamic language invokes an instance method, does not check the type, and can be called as long as the method exists and the parameter is correct.Understand:Python provides an open () function that opens a disk file and returns a file object. The file object has a read () method to read the contents of the files:For example, read the contents from a file and parse it into JSON results:Import JSONf = open

archiveContains‘‘‘All the py_modules,packages,script options imply the Python source fileAll C source files listed in the Ext_modules optionFiles that conform to test/test*.py modeReadme,readme.txt,setup.py,setup.cfg file‘‘‘If the package is managed by subversion or CVS, and the. SVN folder is located to find the files it contains, Sdist will create a manifest file that lists all the files, and then file them for processing.The following rulesInclude

isinstance (self.text,list):If Len (self.text) Self.text= "Self.text=[w for W in Self.text If Len (w) >2]def logger (insetace,method,results):print ' calling%s '%method.__name__Return Truedef add_sequen_ce (name,sequence):SetAttr (Textprocess,name,chainer ([GetAttr (Textprocess,n) for n in Sequence],logger))#add_sequen_ce用来动态的定义一个新链式调用方法的描述符, the result of this combination can be saved in the class definition, as followsAdd_sequen_ce (' Simoke_clean ', (' Split ', ' Trshold '))My=textprocess ('

(‘received from %s:%s.‘ % addr) s.sendto(b‘hello,%s!‘ % data, addr)Create ClientCreate a socket that can be exchanged directly with the server for data exchange.# coding:utf-8import sockets = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)for data in [b‘hello‘, b‘world‘,b‘python‘,b‘android‘,b‘java‘]: # 发送数据 s.sendto(data, (‘127.0.0.1‘, 9999)) # 接收数据， print(s.recv(1024).decode(‘utf-8‘))s.close()得到：hello,hello!hello,world!hello,python!he

, which completely eliminates the overhead of copying these file descriptors on system calls.Another essential improvement is the epoll adoption of event-based readiness notification methods. In Select/poll, the kernel scans all monitored file descriptors only after a certain method is called, and Epoll registers a file descriptor beforehand with Epoll_ctl (), once it is ready based on a file descriptor, The kernel uses a callback mechanism like callback to quickly activate the file descriptor a

_remove_stop_words (self,words):Raise Notimplementederrordef _stem_words (self,words):Raise Notimplementederrordef _frequency (self,setemmed_words):counts={}For word in Setemmed_words:Counts[word]=counts.get (word,0) +1#BasicIndex实现如下:From Itertools import GroupByClass Basicindex (Indexer):_stop_words= (' He ', ' she ', ' is ', ' and ', ' or ')def _remove_stop_words (self,words):return (word for word in words if Word is not in self._stop_words)def _stem_words (self,words):Return ((Len (word) >2

meta-class inherits from the type def __new__(cls,name,bases,attrs): attrs['Say_'+name]=LambdaSelf,value,saying=name:Print(saying+','+value+'!') returnType.__new__(cls,name,bases,attrs)#Create a Hello class from Saymetaclass#Note that in addition to the first parent class, the parameter must be marked with a metaclass= to indicate the class used by the#because the class name here is Hello#so this Hello class has a property of "Say_hello"#This property is also a method that is equivale

conn.commit () cursor.close () Conn.close ()B. Stored Procedures with parametersImport Pymysql conn = Pymysql.connect (host= ' 127.0.0.1 ', port=3306, user= ' root ', passwd= ', db= ' tkq1 ') cursor = Conn.cursor (cursor=pymysql.cursors.dictcursor) cursor.callproc (' P1 ', args= (1, 3, 4)) #获取执行完存储的参数, Parameter @ begins with Cursor.execute ("Select @p1, @_p1_1,@_p1_2,@_p1_3") #{u ' @_p1_1 ': $, U ' @p1 ': None, U ' @_p1_2 ': 103, U ' @_p1_3 ': 24}row_1 = Cursor.fetchone () print row_1conn.com