blocks|key|1477579|text|正如在PEP中提到的，静态类型检查是函数注释可以用于的可能应用程序之一，但他们将如何做的决定留给了第三方库。也就是说，在核心python中不会有正式的实现。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1477580|就第三方实现而言，有一些代码片段(如http://code.activestate.com/recipes/572161/)似乎可以很好地完成这项工作。|offset|length|1477581|编辑：|1477582|需要注意的是，检查行为比检查类型更可取，因此我认为静态类型检查并不是一个好主意。我上面的回答是为了回答这个问题，而不是因为我会用这种方式检查自己的类型。|1477583|entityMap|0|LINK|mutability|MUTABLE|url|http://code.activestate.com/recipes/572161/^0|0|I|17|0|0|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@]|9|@$D|T|E|U|1|V]]|A|$]]|$1|F|3|G|5|6|7|W|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|X|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|Q]]]]

As mentioned in that PEP, static type checking is one of the possible applications that function annotations can be used for, but they're leaving it up to third-party libraries to decide how to do it. That is, there isn't going to be an official implementation in core python.

As far as third-party implementations are concerned, there are some snippets (such as <a href="http://code.activestate.com/recipes/572161/" rel="noreferrer">http://code.activestate.com/recipes/572161/</a>), which seem to do the job pretty well.

EDIT:

As a note, I want to mention that checking behavior is preferable to checking type, therefore I think static typechecking is not so great an idea. My answer above is aimed at answering the question, not because I would do typechecking myself in such a way.

blocks|key|1477628|text|Python中的“静态类型”只能在运行时进行类型检查，这意味着它会降低应用程序的运行速度。因此，您不希望将其作为一般情况。相反，您需要一些方法来检查它的输入。这可以通过简单的断言很容易完成，或者使用装饰器，如果你(错误地)认为你很需要它。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1477629|除了静态类型检查，还有一种替代方案，那就是使用像Zope组件架构这样的面向方面的组件架构。而不是检查类型，而是调整它。因此，不是：|1477630|assert+isinstance(theobject,+myclass)|code-block|syntax|javascript|1477631|您可以执行以下操作：|1477632|theobject+=+IMyClass(theobject)|1477633|如果对象已经实现了IMyClass，则不会发生任何事情。如果不是，则会查找一个将对象包装为IMyClass的适配器，并使用该适配器代替该对象。如果找不到适配器，则会出现错误。|1477634|这结合了Python的动态性和以特定方式拥有特定类型的愿望。|1477635|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|V|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|W|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|X|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|Y|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

"Static typing" in Python can only be implemented so that the type checking is done in run-time, which means it slows down the application. Therefore you don't want that as a generality. Instead you want some of your methods to check it's inputs. This can be easily done with plain asserts, or with decorators if you (mistakenly) think you need it a lot.

There is also an alternative to static type checking, and that is to use an aspect oriented component architecture like The Zope Component Architecture. Instead of checking the type, you adapt it. So instead of:

<pre><code>assert isinstance(theobject, myclass)
</code></pre>

you do this:

<pre><code>theobject = IMyClass(theobject)
</code></pre>

If theobject already implements IMyClass nothing happens. If it doesn't, an adapter that wraps whatever theobject is to IMyClass will be looked up, and used instead of theobject. If no adapter is found, you get an error.

This combined the dynamicism of Python with the desire to have a specific type in a specific way.

blocks|key|1263032|text|这不是对问题的直接回答，但我发现了一个Python+fork，它添加了静态类型：mypy-lang.org，当然不能依赖它，因为它仍然很小，但很有趣。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1263033|entityMap|0|LINK|mutability|MUTABLE|url|http://www.mypy-lang.org/^0|14|D|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

This is not an answer to question directly, but I found out a Python fork that adds static typing: <a href="http://www.mypy-lang.org/" rel="noreferrer">mypy-lang.org</a>, of course one can't rely on it as it's still small endeavor, but interesting.

blocks|key|1477708|text|当然，静态类型看起来有点"unpythonic“，我并不总是使用它。但在某些情况下(例如嵌套类，就像领域特定的语言解析一样)，它确实可以加快开发速度。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1477709|那么我更喜欢使用这个post*中解释的beartype。它附带了一个git+repo，测试和解释它能做什么，不能做什么……我喜欢这个名字;)|offset|length|1477710|*请不要注意Cecil关于为什么Python在这种情况下没有附带电池的咆哮。|1477711|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/37961120/4680402|1|https://gist.github.com/leycec/3d48cc60e7d5fe8860b077acb067dc54^0|0|A|4|0|J|8|1|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@]|9|@$D|T|E|U|1|V]|$D|W|E|X|1|Y]]|A|$]]|$1|F|3|G|5|6|7|Z|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|10|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|O]]|P|$5|K|L|M|A|$N|Q]]]]

Sure, static typing seems a bit "unpythonic" and I don't use it all the time. But there are cases (e.g. nested classes, as in domain specific language parsing) where it can really speed up your development. 

Then I prefer using <a href="https://gist.github.com/leycec/3d48cc60e7d5fe8860b077acb067dc54" rel="nofollow noreferrer">beartype</a> explained in this <a href="https://stackoverflow.com/a/37961120/4680402">post</a>*. It comes with a git repo, tests and an explanation what it can and what it can't do ... and I like the name ;) 

* Please don't pay attention to Cecil's rant about why Python doesn't come with batteries included in this case.

I didn't really pay as much attention to Python 3's development as I would have liked, and only just noticed some interesting new syntax changes. Specifically from <a href="https://stackoverflow.com/questions/1269795/unusual-speed-difference-between-python-and-c/1271927#1271927">this SO answer</a> function parameter annotation:

<pre><code>def digits(x:'nonnegative number') -&gt; "yields number's digits":
 # ...
</code></pre>

Not knowing anything about this, I thought it could maybe be used for implementing static typing in Python!

After some searching, there seemed to be a lot discussion regarding (entirely optional) static typing in Python, such as that mentioned in <a href="http://www.python.org/dev/peps/pep-3107/" rel="noreferrer">PEP 3107</a>, and <a href="http://www.artima.com/weblogs/viewpost.jsp?thread=85551" rel="noreferrer">"Adding Optional Static Typing to Python"</a> (and <a href="http://www.artima.com/weblogs/viewpost.jsp?thread=86641" rel="noreferrer">part 2</a>)

..but, I'm not clear how far this has progressed. Are there any implementations of static typing, using the parameter-annotation? Did any of the parameterised-type ideas make it into Python 3?

Python 3 and static typing

Python

我并没有像我希望的那样关注Python3的开发，只是注意到了一些有趣的新语法变化。特别是在函数参数注释中：def digits(x:'nonnegative number') -> "yields number's digits":    # ...我对此一无所知，我想它也许可以用来在Python中实现静态类型！经过一...

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