使用Python中的类对函数进行分组 [英] Grouping Functions by Using Classes in Python

问题描述

我已经成为Python科学程序员几年了，随着我的程序越来越大，我发现自己遇到了一个特定的问题.我是自学成才的，所以我从未接受过任何正式的培训，并且真正地花了一些时间适当"地使用Python进行常规"编码.

I have been a Python Scientific Programmer for a few years now, and I find myself coming to a sort specific problem as my programs get larger and larger. I am self taught so I have never had any formal training and spent any time really on 'conventions' of coding in Python "properly".

无论如何，到目前为止，我发现自己总是创建一个utils.py文件，该文件存储了程序使用的所有已定义函数.然后，我发现自己将这些功能归为各自的目的.我知道对事物进行分组的一种方法当然是使用类，但是我不确定我的策略是否与实际应使用的类相抵触.

Anyways, to the point, I find myself always creating a utils.py file that I store all my defined functions in that my programs use. I then find myself grouping these functions into their respective purposes. One way of I know of grouping things is of course using Classes, but I am unsure as to whether my strategy goes against what classes should actually be used for.

假设我有一堆函数，它们的功能大致相同，如下所示:

Say I have a bunch of functions that do roughly the same thing like this:

def add(a,b):
    return a + b

def sub(a,b):
    return a -b

def cap(string):
    return string.title()

def lower(string):
    return string.lower()

现在显然，这4个函数可以看作是做两个单独的目的，一个是计算，另一个是格式化.这就是逻辑告诉我要执行的操作，但是由于我不想初始化与该类永远对应的变量，因此必须解决该问题.

Now obviously these 4 functions can be seen as doing two seperate purposes one is calculation and the other is formatting. This is what logic tells me to do, but I have to work around it since I don't want to initialise a variable that corresponds to the class evertime.

class calc_funcs(object):

    def __init__(self):
        pass

    @staticmethod
    def add(a,b):
        return a + b

    @staticmethod
    def sub(a, b):
        return a - b

class format_funcs(object):
    def __init__(self):
        pass

    @staticmethod
    def cap(string):
        return string.title()

    @staticmethod
    def lower(string):
        return string.lower()

通过这种方式，我现在将这些方法分组"到一个不错的程序包中，该程序包可以根据它们在程序中的作用来更快地找到所需的方法.

This way I have now 'grouped' these methods together into a nice package that makes finding desired methods much faster based on their role in the program.

print calc_funcs.add(1,2)
print format_funcs.lower("Hello Bob")

不管怎么说，我觉得这是一种非常"unpython-y"的处理方式，而且感觉很混乱.我要考虑正确的方法还是有其他方法?

However that being said, I feel this is a very 'unpython-y' way to do things, and it just feels messy. Am I going about thinking this the right way or is there an alternate method?

推荐答案

另一种方法是制作一个 util package 并将您的函数拆分为该包中的不同模块.软件包的基础知识:创建一个目录(其名称将为软件包名称)并在其中放置一个特殊文件，即 __ init __.py 文件.该可以包含代码，但是对于基本的软件包组织而言，它可以是一个空文件.

Another approach is to make a util package and split up your functions into different modules within that package. The basics of packages: make a directory (whose name will be the package name) and put a special file in it, the __init__.py file. This can contain code, but for the basic package organization, it can be an empty file.

my_package/
  __init__.py
  module1.py/
  modle2.py/
  ...
  module3.py

假设您位于工作目录中

mkdir util
touch util/__init__.py

然后在您的 util 目录中，创建 calc_funcs.py

Then inside your util directory, make calc_funcs.py

def add(a,b):
    return a + b

def sub(a,b):
    return a -b

和 format_funcs.py :

def cap(string):
    return string.title()

def lower(string):
    return string.lower()

现在，从您的工作目录中，您可以执行以下操作:

And now, from your working directory, you can do things like the following:

>>> from util import calc_funcs
>>> calc_funcs.add(1,3)
4
>>> from util.format_funcs import cap
>>> cap("the quick brown fox jumped over the lazy dog")
'The Quick Brown Fox Jumped Over The Lazy Dog'

已修改以添加

但是，请注意，如果我们重新启动解释器会话，则:

Edited to add

Notice, though, if we restart the interpreter session:

>>> import util
>>> util.format_funcs.cap("i should've been a book")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: module 'util' has no attribute 'format_funcs'

这就是 __ init __.py 的目的！

在 __ init __.py 中，添加以下内容:

import util.calc_funcs, util.format_funcs

现在，再次重新启动解释器:

Now, restart the interpreter again:

>>> import util
>>> util.calc_funcs.add('1','2')
'12'
>>> util.format_funcs.lower("I DON'T KNOW WHAT I'M YELLING ABOUT")
"i don't know what i'm yelling about"

是的！我们可以通过易于导入的方式灵活控制名称空间！基本上， __ init __.py 与类定义中的 __ init __ 方法类似.

Yay! We have flexible control over our namespaces with easy importing! Basically, the __init__.py plays an analogous role to the __init__ method in a class definition.

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