python如何自创模组 python 创建模块

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jojo 2024-03-04 11:40:05

文章标签 python如何自创模组 python java 编程语言人工智能 文章分类 Python 后端开发

python 创建模块

by Hari Santanam

通过Hari Santanam

(Let’s get classy: how to create modules and classes with Python)

In object-oriented computer languages such as Python, classes are basically a template to create your own objects. Objects are an encapsulation of variables and functions into a single entity. Objects get their variables and functions from classes.

在诸如Python之类的面向对象的计算机语言中，类基本上是创建自己的对象的模板。对象是将变量和函数封装到单个实体中的方法。对象从类中获取变量和函数。

Say what?

说什么？

Here are some examples that will help you understand — read on. There is also an interactive code shell, simply press the “Run” button at the top of the specific window.

这里有一些例子，可以帮助您理解-继续阅读。还有一个交互式代码外壳，只需按特定窗口顶部的“运行”按钮即可。

The simplest way to describe classes and how to use them is this:

描述类以及如何使用它们的最简单方法是：

Imagine you have great powers. You create a species (“class”).

想象一下您拥有强大的力量。您创建一个物种(“类”)。

Then you create attributes for that species (“properties”) — height, weight, limbs, color, powers, and so on.

然后，为该物种创建属性(“属性”)—身高，体重，四肢，颜色，力量等。

Then you create an instance of that species — Fido the dog, Drogon from Game of Thrones, and so on. Then you work with these instances:

然后，创建该物种的一个实例-狗Fido，《权力的游戏》中的德罗贡，等等。然后，您可以使用以下实例：

In a game, for instance, they would engage in action, interact, using their attributes.
In a banking app, they would be the different transactions.
In a vehicle buy/sell/trade/lease app, the vehicle class could then spawn sub-classes such as cars. Each would have attributes such as mileage, options, features, color, and trim.

You can already see why this is useful. You are creating, re-using, adapting, and enhancing items in a very efficient, logical, and useful way.

您已经知道为什么这很有用。您正在以非常有效，合乎逻辑和有用的方式创建，重复使用，调整和增强项目。

By now, you have probably realized that this is a way to classify and group, one that that is similar to how humans learn:

到目前为止，您可能已经意识到，这是一种分类和分组的方法，类似于人类的学习方式：

Animals are living things that are not human or trees, in a basic sense
then you move on to different types of animals — dogs, cats are probably the first animals most of us learnt about
then you move to different attributes of animals — shapes, sizes, sounds, appendages and so on.

For instance, when you were a child, your first understanding of a dog was probably something with four legs that barked. Then you learnt to distinguish that some were real dogs, others were toys. That this “dog” concept contained many types.

例如，当您还是个孩子的时候，您对狗的最初了解可能是四脚吠叫的东西。然后，您学会了区分一些是真狗，其他是玩具。该“狗”概念包含许多类型。

Creating and using classes is basically:

创建和使用类基本上是：

building a template to put “things” in — a classification
which can then be operated on. For example, pulling up all the people with dogs that you could request to link to a blog on pets, or all bank clients who might be good prospects for a new credit card.

The main point here is classes are objects that can produce instances of those templates, on which operations and methods can be applied. It is an excellent way to conceptualize, organize, and build a hierarchy for any organization or process.

这里的重点是类是可以生成这些模板实例的对象，可以在其上应用操作和方法。这是为任何组织或流程概念化，组织和构建层次结构的绝佳方法。

As our world gets more complex, this is a way to mimic that complexity from a hierarchical perspective. It also builds a deeper understanding of the processes and interactions for business, technical, and social settings from a virtual information technology point.

随着我们的世界变得越来越复杂，这是一种从层次结构角度模仿这种复杂性的方法。它还从虚拟信息技术的角度更深入地了解了业务，技术和社交环境的流程和交互。

An example might be a video game you create. Each character could be a “class”, with its own attributes, that interacts with instances of other classes. King George of the “King” class might interact with Court Jester Funnyman of the “Clown” class, and so on. A King might have a royal “servant” class, and a “servant” class would always have a “King” class, for example.

例如，您创建的视频游戏。每个字符可以是具有自己属性的“类”，可以与其他类的实例进行交互。 “国王”级的乔治国王可能会与“小丑”级的Jester Funnyman交往，以此类推。例如，国王可能拥有皇家“仆人”阶层，而“仆人”阶层将始终具有“国王”阶层。

This is what we will do:

这就是我们要做的：

create a class and use it
create a module and move the class creation and initiation to the module
call the module in a new program to use the class

The code is available in GitHub here.

该代码可从GitHub 此处获得。

#TSB - Create Class in Python - rocket positions (x,y) and graph

#some items and comments bolded to call attention to processimport matplotlib.pyplot as plt

class Rocket():  def __init__(self, x=0, y=0):    #each rocket has (x,y) position; user or calling function has choice    #of passing in x and y values, or by default they are set at 0    self.x = x    self.y = y      def move_up(self):    self.y += 1      def move_down(self):    self.y -= 1      def move_right(self):    self.x += 1      def move_left(self):    self.x -= 1

#Make a series of rockets - x,y positions, I am calling it rocketrockets=[]rockets.append(Rocket())rockets.append(Rocket(0,2))rockets.append(Rocket(1,4))rockets.append(Rocket(2,6))rockets.append(Rocket(3,7))rockets.append(Rocket(5,9))rockets.append(Rocket(8, 15))  #Show on a graph where each rocket is

for index, rocket in enumerate(rockets):  #original position of rockets  print("Rocket %d is at (%d, %d)." % (index, rocket.x, rocket.y))  plt.plot(rocket.x, rocket.y, 'ro', linewidth=2, linestyle='dashed', markersize=12)  #move the 'rocket' one up  rocket.move_up()  print("New Rocket position %d is at (%d, %d)." % (index, rocket.x, rocket.y))  #plot the new position  plt.plot(rocket.x, rocket.y, 'bo', linewidth=2, linestyle='dashed', markersize=12)  #move the rocket left, then plot the new position  rocket.move_left()  plt.plot(rocket.x, rocket.y, 'yo', linewidth=2, linestyle='dashed', markersize=12)

#show graph legend to match colors with positionplt.gca().legend(('original position','^ - Moved up', '< - Moved left'))plt.show()#plt.legend(loc='upper left')

Now let us create a module and move some of the code above to the module. Any time we need to create this simple set of x,y coordinates in any program, we can use the module to do so.

现在，让我们创建一个模块并将上面的一些代码移至该模块。每当我们需要在任何程序中创建此简单的x，y坐标集时，都可以使用该模块来完成。

(What is a module and why do we need it?)

A module is a file containing Python definitions and statements. Module is Python code that can be called from other programs for commonly used tasks, without having to type them in each and every program that uses them.

模块是包含Python定义和语句的文件。模块是可以从其他程序中调用以执行常用任务的Python代码，而不必在使用它们的每个程序中都键入它们。

For example, when you call “matplotlib.plot”, you are calling a package module. If you didn’t have this module you would have to define the plot functionality in every program that used a plot graph.

例如，当您调用“ matplotlib.plot”时，您正在调用程序包模块。如果没有该模块，则必须在每个使用绘图图的程序中定义绘图功能。

From the Python documentation:

从Python 文档中：

If you quit from the Python interpreter and enter it again, the definitions you have made (functions and variables) are lost. Therefore, if you want to write a somewhat longer program, you are better off using a text editor to prepare the input for the interpreter and running it with that file as input instead.This is known as creating a script. As your program gets longer, you may want to split it into several files for easier maintenance. You may also want to use a handy function that you’ve written in several programs without copying its definition into each program.
如果从Python解释器退出并再次输入，则所做的定义(函数和变量)将丢失。因此，如果要编写更长的程序，最好使用文本编辑器为解释器准备输入，然后以该文件作为输入运行它，这称为创建脚本。随着程序时间的延长，您可能需要将其拆分为多个文件，以便于维护。您可能还想使用在多个程序中编写的便捷功能，而无需将其定义复制到每个程序中。
To support this, Python has a way to put definitions in a file and use them in a script or in an interactive instance of the interpreter. Such a file is called a module; definitions from a module can be imported into other modules or into the main module (the collection of variables that you have access to in a script executed at the top level and in calculator mode).
为此，Python提供了一种将定义放入文件中并在脚本或解释器的交互式实例中使用它们的方法。这样的文件称为模块；可以将模块中的定义导入其他模块或主模块(您可以在顶层和计算器模式下执行的脚本中访问的变量集合)。

Here’s our simple module. It takes the class creation and the functions to move an instance of that class from the program above and into its own class. We will then use this in a new program simply by calling and referencing this module:

这是我们的简单模块。它需要类的创建和函数才能将该类的实例从上方的程序移至其自己的类中。然后，我们只需调用并引用此模块即可在新程序中使用它：

Notice what we did above:

注意我们上面所做的：

created and initialized the class
created a function to move an instance of the class in the four major directions (up, down, right, left) and the increments — as parameters, or arguments to the function
created another function to calculate the distance between two instances of the class, using the graph distance formula

Here’s how we will use the new module to re-write the same program from the first part. Notice in the import section at the beginning, we now import the simple_module1 module that we just created:

这是我们将如何使用新模块从第一部分重新编写同一程序的方法。请注意，在一开始的导入部分中，我们现在导入刚刚创建的simple_module1模块：

Here’s the output from the code using our module. Note that they are the same, except for the chart title and the shape of the position markers, which I changed for comparative purposes.

这是使用我们的模块的代码输出。请注意，除了图表标题和位置标记的形状(出于比较目的而更改)之外，它们是相同的。

That’s great, you may say — what are some other uses for this? One classic example is a bank account. A customer class might contain the name and contact details and — more importantly — the account class would have deposit and withdrawal elements.

您可能会说那太好了–这样做还有其他用途吗？一个典型的例子是银行帐户。客户类别可能包含名称和联系方式，更重要的是，客户类别将包含存款和取款元素。

This is grossly oversimplified but, for illustrative purposes, it is useful. That’s it — create a template, then define instances of that template with details (properties), and add value by adding, subtracting, modifying, moving, and using these instances for your program objectives.

这被大大简化了，但是出于说明目的，它是有用的。就是这样-创建一个模板，然后定义带有细节(属性)的模板实例，并通过添加，减去，修改，移动这些实例并将其用于程序目标来增加价值。

Still wondering about classes? Ok, let’s get “classy” — here’s another simple illustration. We will call this class “Person”. It has only two properties — name and age. We will then add an instance of this with a person’s name and age, and print it. Depending on what your objective is, you can imagine all the other details you might add — for example, marital status and location preferences for a social networking app, job experience in years and industry specialization for a career related app. Press the little triangle below to see it work.

还在想上课吗？好的，让我们“优雅”-这是另一个简单的例子。我们将此类称为“人员”。它只有两个属性-名称和年龄。然后，我们将添加带有人名和年龄的实例，并打印出来。根据您的目标，您可以想象可能会添加的所有其他详细信息，例如，社交网络应用程序的婚姻状况和位置偏好，多年的工作经验以及与职业相关的应用程序的行业专业知识。按下下面的小三角形以查看其工作原理。

So there you have it. You can create many different classes, with parent classes, sub-classes and so on. Thanks for reading — please clap if you liked it. Here are some other references if you would like to learn more:

所以你有它。您可以创建许多不同的类，包括父类，子类等。感谢您的阅读-如果喜欢，请拍手。如果您想了解更多信息，请参考以下其他参考：