Python is an object-oriented programing language, which means that it provides features that support object-oriented programming. It is easy to define object-oriented programming, but we have already seen some of its characteristics:

  • Programs are made up of object definitions and function definitions, and most of the computation is expressed in terms of operations on objects.
  • Each object definition corresponds to some object or concept in the real world, and the functions that operate on that object correspond to the ways real-world objects interact.

For example, the Time class defined to the way people record the time of day, and the functions we defined correspond to the kinds of things people do with times. Similarly, the Point and Rectangle classes correspond to the mathematical concepts of a point and a rectangle.

So far, we have not taken advantage of the features Python provides to support object-oriented programming. Strictly speaking, these features are not necessary. For the most part, they provide an alternative syntax for things we have already done, but in many cases, the alternative is more concise and more accurately conveys the structure of the program.

For example, in the Time program, there is no obvious connection between the class definition and the function definitions that follow. With some examination, it is apparent that every function takes at least one Time object as an argument. This observation is the motivation for methods; a method is a function that is associated with a particular class. For example, we have seen methods for strings, lists, dictionaries and tuples. We will define methods for user-defined types.

Methods are semantically the same as functions, but there are two syntactic differences:

  • Methods are defined inside a class definition in order to make the relationship between the class and the method explicit.
  • The syntax for invoking a method is different from the syntax for calling a function.

Example:

class Time:

    """ represents the time of day

        attributes: hour, minute, second

        method: print_time, increment, int_to_time

                time_to_int, after """

    def print_time(self):

        print('%.2d:%.2d:%.2d' % (self.hour,self.minute,self.second))

    @staticmethod

    def int_to_time(seconds):

        time = Time()

        minute,time.second = divmod(seconds,60)

        time.hour,time.minute = divmod(minute,60)

        return time

    def time_to_int(self):

        return self.second + self.minute*60 + self.hour*3600

    def increment(self,t):

        t1 = self.time_to_int()

        t2 = t.time_to_int()

        time = Time()

        time = Time.int_to_time(t1+t2)

        return time

    def after(self,t):

        return self.time_to_int() > t.time_to_int()

time = Time()

time.hour = 9

time.minute = 4

time.second = 0

from Thinking in Python

Object-oriented features的更多相关文章

  1. Object Oriented Programming python

    Object Oriented Programming python new concepts of the object oriented programming : class encapsula ...

  2. What is Object Oriented Design? (OOD)

    Object Oriented Design is the concept that forces programmers to plan out their code in order to hav ...

  3. CSharpGL - Object Oriented OpenGL in C#

    Object Oriented OpenGL in C#

  4. Java - 面向对象(object oriented)计划 详细解释

    面向对象(object oriented)计划 详细解释 本文地址: http://blog.csdn.net/caroline_wendy/article/details/24058107 程序包括 ...

  5. OO开发思想：面向对象的开发方法(Object oriented,OO）

    面向对象的开发方法(Object oriented,OO)认为是好文章吧,拿来分享一下(转载) 面向对象的开发方法(Object oriented,OO) 从事软件开发的工程 师们常常有这样 的体会: ...

  6. JavaScript: Constructor and Object Oriented Programming

    Constructor :  Grammar: object.constructor Example: Javascript code: 1 function obj1() { this.number ...

  7. 面对对象编程(OOP, Object Oriented Programming)及其三个基本特性

    一千个读者,一千个哈姆雷特.对于面对对象编程,书上都会告诉我们它有三个基本特性,封装,继承,多态,但谈起对这三点的见解,又是仁者见仁智者见智,感觉还是得多去编程中体验把 . 面向对象编程(OOP, O ...

  8. Python学习札记(三十) 面向对象编程 Object Oriented Program 1

    参考:OOP NOTE 1.面向对象编程--Object Oriented Programming,简称OOP,是一种程序设计思想.OOP把对象作为程序的基本单元,一个对象包含了数据和操作数据的函数. ...

  9. 使用一个数组存储一个英文句子"java is an object oriented programing language"

    class fun { public static void main(String[] args) { String str="java is an object oriented pro ...

  10. 《Using Databases with Python》Week1 Object Oriented Python 课堂笔记

    Coursera课程<Using Databases with Python> 密歇根大学 Charles Severance Week1 Object Oriented Python U ...

随机推荐

  1. android学习笔记33——资源ShapeDrawable

    ShapeDrawable ShapeDrawable用于定义一个基本的几何图像(如,矩形.圆形.线条.......). 定义ShapeDrawable的XML文件的根元素是<shape.../ ...

  2. docker配置环境

    debian: curl -sSL https://get.docker.com/ | sh curl -sSL https://get.daocloud.io/docker | sh daoclou ...

  3. WeX5和BeX5比较

    http://wex5.com/cn/wex5和bex5比较/ WeX5和BeX5比较 许多对WeX5和BeX5略有了解得人都知道,WeX5和BeX5是完全共用前端框架技术的.但是WeX5和BeX5是 ...

  4. TMDS协议

    1 概述 1.1    连接结构 图1 TMDS连接结构 数据流中包含了像素和控制数据,发送器在任何给定的输入时钟周期,到底是编码像素数据还是控制数据取决于数据使能信号DE,DE有效时,指示像素数 据 ...

  5. PLSQL_查询SQL的执行次数和频率（案例）

    2014-12-25 Created By BaoXinjian

  6. Linux命令（18）查看当前用户who、whoami、who am i

    首先看命令的使用情况: [@sjs_9_108 ~]$ whoami spider [@sjs_9_108 ~]$ who am i spider pts/ -- : (192.168.1.1) [@ ...

  7. 错误代码2104：无法下载Silverlight应用程序。请查看Web服务器设置

    今天调试Silverlight程序,把ClientBin文件夹下的.xap文件删除后遇到这样一个问题:错误代码2104:无法下载Silverlight应用程序.请查看Web服务器设置.在网上查了一下, ...

  8. 转-安卓中实现两端对齐，中间fill_parent的方法

    安卓中实现两端对齐,中间fill_parent的方法 Java代码:   <?xml version="1.0″ encoding="utf-8″?> <Line ...

  9. MySQL 开启与关闭远程访问&&授权前需执行GRANT USAGE ON *.* TO 'cai'@'%' IDENTIFIED BY 'caigan2015';才能终端访问

    MySQL 开启与关闭远程访问 (1)通过MySQL用户去限制访问 权限系统目的: MySQL基于安全考虑root账户一般只能本地访问,但是在开发过程中可能需要打开root的远程访问权限,今天介绍的就 ...

  10. Tomcat启动过程原理详解

    基于Java的Web 应用程序是 servlet.JSP 页面.静态页面.类和其他资源的集合,它们可以用标准方式打包,并运行在来自多个供应商的多个容器.Web 应用程序存在于结构化层次结构的目录中,该 ...