为什么我要使用inspect.isclass（）？

会： 如果inspect.isclass（s​​ome_class）==真： ... 返回 ### 但这显然不是什么类。我该怎么用？ 谢谢， I discovered the hardway what inspect.isclass() is doing. Consider this nobrainer code: ###import inspect class Abc:def Hello(self):return an_instance=Abc()print inspect.isclass(an_instance)### It took me a while to understand how I can get inspect.isclass to return aTrue (like: inspect.isclass(Abc)). But what good is that? Of course I know Abc is a class, why would I want toinspect it so that it would tell me what I already know? I would have thought this would be the situation I need that for: ###import inspect class Abc:def Hello(self, some_class):# since I don''t know if the argument passed down *is* a class or not, Iwould:if inspect.isclass(some_class)==True:...return### But that obviously isn''t what isclass is for. What should I use? Thanks,推荐答案 > an_instance = Abc（） > an_instance=Abc() 但这有什么用呢？当然我知道Abc是一个班级，为什么我要检查它以便告诉我我已经知道的内容？ 好​​吧，在那种情况下没有理由。出于同样的原因，如果你已经知道an_instance是一个abc的 实例，那么你就不会打电话给你实例（an_instance，abc）。 def你好（self，some_class）：＃因为我不知道传递的论点是*是*是否是一个类，我会如果inspect.isclass（s​​ome_class） ==正确： ... 返回 ### 但这显然不是什么类。我应该使用什么？ But what good is that? Of course I know Abc is a class, why would I want to inspect it so that it would tell me what I already know?Well, for no reason in that case. For the same reason you would notcall isinstance(an_instance, Abc) if you already know an_instance is aninstance of Abc. def Hello(self, some_class): # since I don''t know if the argument passed down *is* a class or not, I would: if inspect.isclass(some_class)==True: ... return ### But that obviously isn''t what isclass is for. What should I use? 嗯，这显然是什么类的;）（顺便说一句，你会是 最好不要将你的条件与True进行比较，除非它真的是你想要的b $ b。 我想另一个例子是类型的断言争论： def foo（someClass）： 断言inspect.isclass（s​​omeClass） ＃其余代码 这样，类型上的错误在开始时处理，并且在它自己记录的代码时间同时处理。该函数也可能有用 在你做一些C ++的情况下 - 比如重载机制。无论如何， isclass，就像iscallable一样，是经常不常用的函数，但是你还是可能需要它们。 此致， Nicolas Well, it''s obviously what isclass is for;) (By the way, you would bebetter not compare your conditions with True, unless it''s really whatyou want). I guess another example would be an assert on the type of argument:def foo(someClass):assert inspect.isclass(someClass)# rest of code This way errors on types are handled at the beginning and at the sametime the code it documenting itself. The function could also be usefulin cases where you do some C++-like overloading mechanism. Anyway,isclass, like iscallable, are functions that are not used often, but youstill might need them. Regards,Nicolas Nicolas， 感谢您的回复。请参阅下面的评论。 " Nicolas Fleury" < NI ****** @ yahoo.com_removethe_>在消息中写道 news：as ******************** @ weber.videotron.net ... Nicolas, Thanks for the response. Please see comment below. "Nicolas Fleury" <ni******@yahoo.com_removethe_> wrote in messagenews:as********************@weber.videotron.net... an_instance = Abc（） an_instance=Abc()但这有什么用呢？当然我知道Abc是一个班级，为什么我要b $ b想要检查它以便告诉我我已经知道的东西？ But what good is that? Of course I know Abc is a class, why would Iwant to inspect it so that it would tell me what I already know? 好吧，没有理由案件。出于同样的原因，如果你已经知道an_instance是Abc的实例，你就不会调用isinstance（an_instance，abc）。 Well, for no reason in that case. For the same reason you would not call isinstance(an_instance, Abc) if you already know an_instance is an instance of Abc. def你好（自我， some_class）：＃因为我不知道传递的参数是*是*类还是不是，我会：如果inspect.isclass（s​​ome_class）== True： ... 返回 ### 但这显然不是什么类。我应该使用什么？ def Hello(self, some_class): # since I don''t know if the argument passed down *is* a class ornot, I would: if inspect.isclass(some_class)==True: ... return ### But that obviously isn''t what isclass is for. What should I use? 嗯，这显然是isclass的用途;）（顺便说一下，你最好不要将你的条件与True比较，除非它真的是你想要的。） Well, it''s obviously what isclass is for;) (By the way, you would be better not compare your conditions with True, unless it''s really what you want). 但是，无论如何，inspect.isclass（s​​ome_class）都会返回False。这就是为什么 我很困惑。 我得到isclass返回True的唯一方法是在我的 例子。 我想另一个例子是关于参数类型的断言： def foo（someClass）：断言检查。 isclass（s​​omeClass）＃其余代码 但总会失败！ （我只是试过了。） 这样，类型上的错误在开始时处理，并且在它自己编写代码的同一时间处理。在你做一些C ++的情况下，这个函数也很有用 - 比如重载机制。无论如何， isclass，就像iscallable一样，是经常不常用的函数，但是你仍然可能需要它们。 问候， Nicolas But inspect.isclass(some_class) returns a False no matter what. That''s whyI am confused. The only way I get isclass to return True is inspect.isclass(Abc) in myexample. I guess another example would be an assert on the type of argument: def foo(someClass): assert inspect.isclass(someClass) # rest of code But that would always fail! (I just tried it). This way errors on types are handled at the beginning and at the same time the code it documenting itself. The function could also be useful in cases where you do some C++-like overloading mechanism. Anyway, isclass, like iscallable, are functions that are not used often, but you still might need them. Regards, Nicolas 这是我写的： 我想另一个例子是关于参数类型的断言： def foo（someClass）：断言inspect.isclass（s​​omeClass）＃rest of code I guess another example would be an assert on the type of argument:def foo(someClass): assert inspect.isclass(someClass) # rest of code 但总会失败！ （我刚试过它。） But that would always fail! (I just tried it). 你确定你没有通过实例而不是课程吗？请记住， 类也是Python中的对象： Are you sure you haven''t pass an instance instead of a class? Remember,classes are also objects in Python: import inspect A类：传递 .... def foo（a）：断言inspect.isclass（a） .... foo（A） 工作正常，有道理，不是吗？当然，如果我传递一个实例 而不是一个类它会失败： myA = A（） foo（myA） import inspect class A: pass.... def foo(a): assert inspect.isclass(a).... foo(A) Works fine and makes sense, no? Of course, if I pass an instanceinstead of a class it would fail: myA = A() foo(myA) 回溯（最近一次调用最后一次）： 文件"< stdin>"，第1行，在？ 文件"< stdin>"，第1行，在foo中 AssertionError 也许您的问题是在什么情况下通过课程可能有用吗？ 有很多例子，一旦你习惯了这种能力，它就可以实现强大的功能。一个简单的例子就是生成 文档;因为你通常想要你的课程，而不是实例。所以做一些事情是有道理的： def writeHtmlDoc（file，someClass）：... 问候， Nicolas Traceback (most recent call last):File "<stdin>", line 1, in ?File "<stdin>", line 1, in fooAssertionError Maybe your question is in what situations passing a class can be useful?There''s many examples and once you''re used to that capability it canbe powerful. One simple example could be the generation ofdocumentation; since you usually want to doc your classes, notinstances. So it would make sense to do something like: def writeHtmlDoc(file, someClass): ... Regards,Nicolas 这篇关于为什么我要使用inspect.isclass（）？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！