Python面向对象编程总结（上）

标签： python java 面向对象编程面向对象编程2016-02-16 10:36 231人阅读评论(0) 收藏举报 Python面向对象编程总结（上）

分类： python（4）

在我学习python之前一直认为python是脚本型语言，不能用面相对象的方法进行编程，当我学习了python之后我发现我错了，python不但支持面相对象而且使用的人还挺多的。我从接触编程开始就是学习的Java语言，所以面相对象编程的思想在我的脑海里根深蒂固，让我一下从面向对象编程转换到面向过程编程还有一些不适应呢，所以我就来总结一下python面向对象编程的方法和过程。我将按照面向对象的构成要素来分析，依次为类和实例、属性、方法、封装、继承、多态，如果有什么问题还请大家积极指出，我所用的版本为python2.7！

一、类和实例

面向对象是一种编程思想，它将现实生活中的事物映射到程序世界中，所以我们可以使用现实生活中的思想来考虑编程问题，这使我们编程变得更加容易，毕竟我们都已经在现实生活中生活了几十年了嘛。

我们来看一下python中类的基本形式。

<code class="hljs python has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Movie</span><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(object)</span>:</span>

    <span class="hljs-function" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">def</span> <span class="hljs-title" style="box-sizing: border-box;">__init__</span><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(self,name,length)</span>:</span>
        self.name = name
        self.length = length

    <span class="hljs-function" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">def</span> <span class="hljs-title" style="box-sizing: border-box;">print_name</span><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(self)</span>:</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">print</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'电影的名称是:%s'</span> % (self.name,)</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li></ul>

class Movie(object): 是固定写法，class表明正在声明的是一个类，Movie是类名，（object）表示继承自那些父类，就行java一样，所有的类都是继承自object类的，所以如果你写的不继承自其他的类就将其写成继承自object，当继承自object，括号连同括号里的object都可以省略写成：class Movie:

第一个方法__init__是构造方法，构造方法的第一个参数永远是self，表示这个类的对象本身，真正构造对象时，self这个参数不用写，python编译器会自己加上去，构造方法的作用就是对self对象进行赋值，如上面的将电影的名字和长度赋给self。

对于上面的Movie类我们可以用下面的代码来调用它：

<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> OOP

movie = OOP.Movie(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'大圣归来'</span>,<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">90</span>)
movie.print_name()</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li></ul>

输出的结果是：电影的名称是:大圣归来

如果不需要给对象传递什么参数，那么构造方法也是可以省略的，例如：

<code class="hljs python has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Movie</span><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(object)</span>:</span>

    <span class="hljs-function" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">def</span> <span class="hljs-title" style="box-sizing: border-box;">print_info</span><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(self)</span>:</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">print</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'这是一个电影的类'</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li></ul>

这样在构造对象时就不用传递任何的参数例如：

<code class="hljs avrasm has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">import OOP

movie = OOP<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.Movie</span>()
movie<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.print</span>_info()</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li></ul>

输出的结果为：这是一个电影的类

二、属性

1、实例属性

实例属性是归对象所有，每个对象都有自己的一套属性，不同对象之间的实例属性不会相互干扰。在python中，在__init__方法中声明的属性就是实例属性。当然，你也可以在类中的任何一个方法中，使用self.var=something 的方式声明实例属性，但是我个人觉得这样会使程序非常混乱，容易出错，下面用这个例子来看一下：

OPP

<code class="hljs python has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"># -*- coding: utf-8 -*-</span>

<span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Movie</span><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(object)</span>:</span>

    <span class="hljs-function" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">def</span> <span class="hljs-title" style="box-sizing: border-box;">__init__</span><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(self,name,length)</span>:</span>
        self.name = name
        self.length = length

    <span class="hljs-function" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">def</span> <span class="hljs-title" style="box-sizing: border-box;">print_name</span><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(self)</span>:</span>
        self.aaa = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'123'</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">print</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'电影的名称是:%s'</span> % (self.name,)</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li></ul>

OOPTest

<code class="hljs python has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"># -*- coding: utf-8 -*-</span>

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> OOP

movie1 = OOP.Movie(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'大圣归来'</span>,<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">90</span>)
movie2 = OOP.Movie(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'美人鱼'</span>,<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">120</span>)

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">print</span> movie1.name
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">print</span> movie2.name

movie1.print_name()
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">print</span> movie1.aaa <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#只有在调用了print_name方法之后，aa才会被定义</span>

movie1.name=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'风声'</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">print</span> movie1.name
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">print</span> movie2.name <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#movie1的改变并未影响到movie2</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li></ul>

输出结果：
大圣归来
美人鱼
电影的名称是:大圣归来
123
风声
美人鱼

2、类属性

类属性是归这个类所有的，所有的实例都共享着一个变量，如果一个实例改变了类属性的值，那么所有的实例都会受到影响。类属性的声明独立于所有方法，声明方法如下：

OOP

<code class="hljs python has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"># -*- coding: utf-8 -*-</span>

<span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Movie</span><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(object)</span>:</span>

    count = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span> <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#类属性</span>

    <span class="hljs-function" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">def</span> <span class="hljs-title" style="box-sizing: border-box;">__init__</span><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(self,name,length)</span>:</span>
        self.name = name
        self.length = length

    <span class="hljs-function" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">def</span> <span class="hljs-title" style="box-sizing: border-box;">print_name</span><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(self)</span>:</span>
        self.aaa = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'123'</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">print</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'电影的名称是:%s'</span> % (self.name,)</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li></ul>

上面的count就是一个类属性，类属性就类似于java中static变量，可以使用类名.count的方式进行调用，当然也可以通过实例.count的方式进行调用，类属性一般用于计数对象，或者不同实例之间共享变量，看下面的例子来理解一下类变量。

<code class="hljs axapta has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;"># -*- coding: utf-8 -*-</span>

import OOP

movie1 = OOP.Movie(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'大圣归来'</span>,<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">90</span>)
movie2 = OOP.Movie(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'美人鱼'</span>,<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">120</span>)

print OOP.Movie.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">count</span> <span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#1 通过类名.count的方式进行调用</span>
print movie2.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">count</span> <span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#1 通过实例.count的方式进行调用</span>

movie1.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">count</span> = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">3</span>
print OOP.Movie.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">count</span> <span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#1</span>
print movie1.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">count</span> <span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#3</span>
print movie2.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">count</span> <span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#1</span>

OOP.Movie.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">count</span>=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">3</span>
print OOP.Movie.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">count</span> <span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#3</span>
print movie1.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">count</span> <span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#3</span>
print movie2.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">count</span> <span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#3</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li></ul>

注释中是输出的结果，我们可以看到如果使用类名.count的方式进行调用，那么所有的实例中的值都将改变，但是如果通过实例.count的方式进行调用，那么只有相应的实例的值发生了改变。

三、方法

Python的方法并不像C#,Java这些编译性语言那样严格的区分静态方法和实例方法。也就是说Python的静态方法，类方法和实例方法只是在调用上有区别，类型和实例都可以调用。

1、实例方法

实例方法可以被类实例调用，通过实例.方法的形式进行调用，这个我们都不陌生了，上面例子中的print_name方法就是实例方法，使用实例方法是传入的参数方法声明时的参数少一个，因为第一个参数self是不用提供的。除此之外实例方法还可以被类调用，形式是类名.方法名(self)，必须手动添加self变量，也就是类的实例。

2、类方法

类方法可以被类和类实例调用，但是类方法无法访问实例变量，只能方法访问类变量，声明时在方法前面加上@classmethod，并且方法中的第一个参数是cls而不是self，和实例方法一样，使用时第一个参数不用传递，python的编译器会自动的加上。类方法更像java中的static方法。

3、静态方法

静态方法可以被类和类实例调用，无法访问实例变量和类变量，只能方法传入进来的参数，声明时在方法前面加上@staticmethod，静态方法没有默认的参数，静态方法有点像函数工具库的作用。

OOP

<code class="hljs python has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"># -*- coding: utf-8 -*-</span>

<span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Movie</span><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(object)</span>:</span>

    count = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>

    <span class="hljs-function" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">def</span> <span class="hljs-title" style="box-sizing: border-box;">__init__</span><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(self,name,length)</span>:</span>
        self.name = name
        self.length = length

    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#实例方法</span>
    <span class="hljs-function" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">def</span> <span class="hljs-title" style="box-sizing: border-box;">print_name</span><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(self)</span>:</span>
        self.aaa = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'123'</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">print</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'电影的名称是:%s'</span> % (self.name,)

    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#类方法</span>
    <span class="hljs-decorator" style="color: rgb(0, 102, 102); box-sizing: border-box;">@classmethod</span>
    <span class="hljs-function" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">def</span> <span class="hljs-title" style="box-sizing: border-box;">print_len</span><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(cls)</span>:</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">print</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'电影的长度是:%d'</span> % (cls.count,)

    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#静态方法</span>
    <span class="hljs-decorator" style="color: rgb(0, 102, 102); box-sizing: border-box;">@staticmethod</span>
    <span class="hljs-function" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">def</span> <span class="hljs-title" style="box-sizing: border-box;">print_info</span><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(str)</span>:</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">print</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'传入的信息是:%s'</span> % (str,)</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li></ul>

OOPTest

<code class="hljs python has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"># -*- coding: utf-8 -*-</span>

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> OOP

movie1 = OOP.Movie(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'大圣归来'</span>,<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">90</span>)

movie1.print_name() <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#通过实例调用实例方法</span>
OOP.Movie.print_name(movie1) <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#如果通过类调用实例方法，必须手动传入实例</span>

OOP.Movie.print_len() <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#通过类调用类方法</span>
movie1.print_len() <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#通过实例调用类方法</span>

OOP.Movie.print_info(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'哈哈'</span>) <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#通过类调用静态方法</span>
movie1.print_info(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'哈哈'</span>) <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#通过实例调用静态方法</span>
</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li></ul>

剩下的还有很多，一次写不完，下一篇在讨论封装、继承和多态，谢谢大家的支持！

秒客网

Python面向对象编程总结（上）

Python面向对象编程总结（上）

1、实例属性

2、类属性

1、实例方法

2、类方法

3、静态方法

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