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Python - Object Oriented

Python - Object Oriented
Python has been an object-oriented language since it existed. Because of this, creating and using classes and objects are downright easy. This chapter helps you become an expert in using Python's object-oriented programming support. If you do not have any previous experience with object-oriented (OO) programming, you may want to consult an introductory course on it or at least a tutorial of some sort so that you have a grasp of the basic concepts. However, here is small introduction of Object-Oriented Programming (OOP) to bring you at speed − Overview of OOP Terminology Class: A user-defined prototype for an object that defines a set of attributes that characterize any object of the class. Creating Classes The class statement creates a new class definition. class ClassName: 'Optional class documentation string' class_suite The class has a documentation string, which can be accessed via ClassName. Example Following is the example of a simple Python class − Creating Instance Objects #! #! #! Syntax #! Related:  Pythondev python

Python syntax and semantics Keywords[edit] Python has the following keywords or reserved words; they cannot be used as identifiers.[3][4] andasassertbreakclasscontinuedefdelelifelseexceptexec (changed to a built-in function in 3.x)False (keyword in 3.x)finallyforfromglobalifimportinislambdaNonenonlocal (added in 3.x)notorpassprint (changed to a built-in function in 3.x)raisereturnTrue (keyword in 3.x)trywhilewithyield As exec and print are functions as of Python 3 they are not reserved words anymore. Indentation[edit] In so-called "free-format" languages, that use the block structure derived from ALGOL, blocks of code are set off with braces ({ }) or keywords. void foo(int x){ if (x == 0) { bar(); baz(); } else { qux(x); foo(x - 1); }} foo function in Python: def foo(x): if x == 0: bar() baz() else: qux(x) foo(x - 1) Python mandates a convention that programmers in ALGOL-style languages often follow. Misleading indentation in C: for (i = 0; i < 20; ++i) a(); b(); c(); Data structures[edit] Base types[edit] Literals[edit]

A Beginner's Python Tutorial/Classes Introduction[edit] One thing that you will get to know about programming, is that programmers like to be lazy. If something has been done before, why should you do it again? That is what functions cover in Python. You've already had your code do something special. Now you want to do it again. Of course, functions have their limitations. That can easily be worked around with normal functions. Chances are that you also have more than one golf club. Or what if you want a golf club, which has added extra features? These problems are what a thing called object-oriented-programming solves. Creating a Class[edit] What is a class? So how do you make these so-called 'classes'? Code Example 1 - defining a class # Defining a class class class_name: [statement 1] [statement 2] [statement 3] [etc.] Makes little sense? Code Example 2 - Example of a Class What you have created is a description of a shape (That is, the variables) and what operations you can do with the shape (That is, the functions).

python recipe: open a file, read it, print matching lines . palewire There are a couple great books available free online but it's pretty tough to start stringing all the fundamentals into a problem-solving script all on your own. So why not write up some simple recipes that attack problems common to our particular tribe? One of the ways computer programming can be of great use to a reporter is as a text parser. We all have more documents than we have time. If it's a one-off effort, you can probably get this done quickly using search tools included in common quality text editors (ex. In that spirit, the following instructions are designed to show you how to use Python to search through a text file (The Sonnets of William Shakespeare), find any lines that contain our sample search term ("love"), and then print out the hits into a new file we can keep as a memento. The one prerequsite for the whole endeavor is that you already have a working installation of Python. If you've got it properly installed, it should return something like 1. 2. 3. 4. #! 5. Voila.

Multiple Function Arguments - Learn Python - Free Interactive Python Tutorial Every function in Python receives a predefined number of arguments, if declared normally, like this: def myfunction(first, second, third): # do something with the 3 variables ... Execute Code It is possible to declare functions which receive a variable number of arguments, using the following syntax: def foo(first, second, third, *therest): print "First: %s" % first print "Second: %s" % second print "Third: %s" % third print "And all the rest... The "therest" variable is a list of variables, which receives all arguments which were given to the "foo" function after the first 3 arguments. First: 1 Second: 2 Third: 3 And all the rest... [4, 5] It is also possible to send functions arguments by keyword, so that the order of the argument does not matter, using the following syntax: The following code yields the following output: The sum is: 6 Result: 1 The "bar" function receives 3 arguments.

Python Sending Email using SMTP Simple Mail Transfer Protocol (SMTP) is a protocol, which handles sending e-mail and routing e-mail between mail servers. Python provides smtplib module, which defines an SMTP client session object that can be used to send mail to any Internet machine with an SMTP or ESMTP listener daemon. Here is a simple syntax to create one SMTP object, which can later be used to send an e-mail − import smtplib smtpObj = smtplib.SMTP( [host [, port [, local_hostname]]] ) Here is the detail of the parameters: host: This is the host running your SMTP server. An SMTP object has an instance method called sendmail, which is typically used to do the work of mailing a message. The sender - A string with the address of the sender.The receivers - A list of strings, one for each recipient.The message - A message as a string formatted as specified in the various RFCs. Example Here is a simple way to send one e-mail using Python script. #! smtplib.SMTP('', 25) Sending an HTML e-mail using Python #! #!

Introduction to Python: Class 5 Page Contents A Python class is created by a class definition, has an associated name space, supports attribute reference, and is callable. class name[(expr[,expr]*)]: suite The class definition is an executable statement and as such can be used whereever an executable statement may occur. Classes have five predefined attributes: The simplest use of classes is as simple Cartesian product types, e.g., the records of Pascal or the structs of C. class foo: a, b, c = 0, "bar", (1,2) Instantiating Classes A class is instantiated by calling the class object: i = foo() print i.a, i.b, i.c In the above, i is an instance of the class foo. i.a = 12 = "yikes" # dynamic attribute creation! Note that new slots, which weren't defined when the class was defined, can be created at will simply by assignment. class foo: pass foo.a = 1 foo.b = 2 Instance Attributes Instances have two predefined attributes: Class Attributes vs Instance Attributes foo.a => 1 i. Suppose we have Cartesian points: cpt = (3,4) Self

9. Classes Compared with other programming languages, Python’s class mechanism adds classes with a minimum of new syntax and semantics. It is a mixture of the class mechanisms found in C++ and Modula-3. Python classes provide all the standard features of Object Oriented Programming: the class inheritance mechanism allows multiple base classes, a derived class can override any methods of its base class or classes, and a method can call the method of a base class with the same name. Objects can contain arbitrary amounts and kinds of data. As is true for modules, classes partake of the dynamic nature of Python: they are created at runtime, and can be modified further after creation. In C++ terminology, normally class members (including the data members) are public (except see below Private Variables and Class-local References), and all member functions are virtual. (Lacking universally accepted terminology to talk about classes, I will make occasional use of Smalltalk and C++ terms. 9.1. 9.2. 9.3.

Why are Python's 'private' methods not actually private Classes and Objects - Learn Python - Free Interactive Python Tutorial Objects are an encapsulation of variables and functions into a single entity. Objects get their variables and functions from classes. Classes are essentially a template to create your objects. A very basic class would look something like this: class MyClass: variable = "blah" def function(self): print "This is a message inside the class." Execute Code We'll explain why you have to include that "self" as a parameter a little bit later. myobjectx = MyClass() Now the variable "myobjectx" holds an object of the class "MyClass" that contains the variable and the function defined within the class called "MyClass". Accessing Object Variables To access the variable inside of the newly created object "MyObject" you would do the following: myobjectx.variable So for instance the below would output the string "blah": print myobjectx.variable You can create multiple different objects that are of the same class(have the same variables and functions defined). myobjecty = MyClass() myobjecty.variable = "yackity"

Python Networking Programming Python provides two levels of access to network services. At a low level, you can access the basic socket support in the underlying operating system, which allows you to implement clients and servers for both connection-oriented and connectionless protocols. Python also has libraries that provide higher-level access to specific application-level network protocols, such as FTP, HTTP, and so on. This chapter gives you understanding on most famous concept in Networking - Socket Programming. What is Sockets? Sockets are the endpoints of a bidirectional communications channel. Sockets may be implemented over a number of different channel types: Unix domain sockets, TCP, UDP, and so on. Sockets have their own vocabulary: The socket Module To create a socket, you must use the socket.socket() function available in socket module, which has the general syntax − s = socket.socket (socket_family, socket_type, protocol=0) Here is the description of the parameters − Server Socket Methods Client Socket Methods

Python from Scratch: Object Oriented Programming Welcome back to lesson four in our Python from Scratch series. This tutorial will assume some prior knowledge of variables, data types, functions and print output. If you're not up to date, check out the previous three articles in the series to catch up. Today, we're going to be delving into the subject of Object Oriented Programming (OOP). Prefer a Screencast? Transcription What is Object Oriented Programming? Python is primarily designed as an object-oriented programming language – but what does ‘object oriented’ actually mean? There are a variety of definitions for the term, and you could talk for literally hours trying to explain the complicated ins and outs, nuances and differences in implementations, but I’ll try to give a quick overview. Broadly, object oriented programming is the concept that, in programming, the objects that we’re manipulating are more important than the logic needed to manipulate those objects. OOP puts objects at the center of the process. Getting Started class pet: