我应该如何在python中向int添加方法？ [英] Should I, and how to, add methods to int in python?
问题描述
（这是一个与学习相关的问题，所以我为什么要做或不做任何事情的建议，以及推荐的资源来使这些事情变得更好，不仅仅是好的。）
(This is a learning related question, so any advice in why should I do or not do anything, as well as recommended resources to get these things better, are more than wellcome.)
我正在尝试在python中学习OOP，并做了一个简单的Time类，如下所示：
I'm trying to learn about OOP in python, and have done a simple "Time" class like this:
class Time(object):
"""A time representation."""
def __init__(self, hours=0, minutes=0, seconds=0):
self.hours = hours
self.minutes = minutes
self.seconds = seconds
def __int__(self):
return self.hours * 3600 + self.minutes * 60 + self.seconds
现在， __ int __ 方法让我从Time实例中获取一个int，表示我执行 int（时间（3,4）时的时间（但以秒为单位） ，5））。顺便说一下，我觉得这很棒。但是，为了使用它，知道如何让int有一个返回Time对象的新方法会很好，所以像 3643.time（）可以完成。
Now, that __int__ method lets me get an int from my "Time" instances that represent the time (but in seconds) when I do int(Time(3, 4, 5)). I find that to be kind of awesome, by the way. But, in order to use this, it would be nice to know how to make an "int" have a new method that returns a "Time" object, so something like 3643.time() could be done.
为什么？
出于各种原因：
Why? For various reasons:
-
因为这样我现在才知道对我来说是什么样的黑魔法。 （这些都强调了让事情发生的事情......以及相关的东西）
Because that way I learn about what for me is like black magic right now. (these underscored things that make things happen... and related stuff)
因为我不知道为什么我不应该这样做。 （请告诉我）
Because I don't know why I shouldn't. (so tell me please)
我想我可以在任何课程之外做以下的事情：
I suppose I could do something like the following outside any class:
def time(seconds):
"""Return an HH:MM:SS stamp of "seconds", where "seconds" should be an int."""
hours, minutes = 0, 0
if seconds >= 3600:
hours, seconds = divmod(int, 3600)
if seconds >= 60:
minutes, seconds = divmod(int, 60)
return "{:02d}:{:02d}:{:02d}".format(hours, minutes, seconds)
但这似乎与这些对象无关，它似乎没有那么多面向对象...所以，我认为可能有更好的方法来处理这种事情。
But that doesn't seem to relate to these objects enough, It doesn't seem that much object oriented... So, I reckon maybe there is a better way to approach this kind of thing.
推荐答案
不，你不能真的将方法添加到int。你可以继承int，并从你的 __ int __ 方法返回它，但这对你没什么帮助，因为调用 int（） on仍然会返回一个常规的int。
No, you cannot really add methods to int. You could subclass int, and return that from your __int__ method, but that won't help you much, since calling int() on that will still return a regular int.
你想使用常规函数转换回时间（）是正确的，但它可能很好，使它成为一个类方法，所以它更明显的相关性：
Your idea of using a regular function to convert back to Time() is right, but it might be nice to make it a classmethod so it's a little more obvious how it relates:
class Time(object):
@classmethod
def from_seconds(cls, seconds):
_hours, _minutes, _seconds = ...
return cls(_hours, _minutes, _seconds)
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