blocks|key|353274|text|更好的方法是:使用inspect.isclass函数。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|353275|>>>+import+inspect
>>>+class+X(object):
...+++++pass
...+
>>>+inspect.isclass(X)
True

>>>+x+=+X()
>>>+isinstance(x,+X)
True
>>>+inspect.isclass(x)
False|code-block|syntax|javascript|353276|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.python.org/library/inspect.html#inspect.isclass^0|9|F|9|F|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@$9|V|A|W|1|X]]|E|$]]|$1|F|3|G|5|H|7|Y|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

Even better: use the <a href="https://docs.python.org/library/inspect.html#inspect.isclass" rel="noreferrer"><code>inspect.isclass</code></a> function.
<pre><code>&gt;&gt;&gt; import inspect
&gt;&gt;&gt; class X(object):
... pass
... 
&gt;&gt;&gt; inspect.isclass(X)
True

&gt;&gt;&gt; x = X()
&gt;&gt;&gt; isinstance(x, X)
True
&gt;&gt;&gt; inspect.isclass(x)
False
</code></pre>

blocks|key|357120|text|>>>+class+X(object):
...+++++pass
...+
>>>+type(X)
<type+'type'>
>>>+isinstance(X,type)
True|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|357121|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>&gt;&gt;&gt; class X(object):
... pass
... 
&gt;&gt;&gt; type(X)
&lt;type 'type'&gt;
&gt;&gt;&gt; isinstance(X,type)
True
</code></pre>

blocks|key|354462|text|inspect.isclass可能是最好的解决方案，很容易看出它是如何实际实现的|type|unstyled|depth|inlineStyleRanges|entityRanges|data|354463|def+isclass(object):
++++"""Return+true+if+the+object+is+a+class.

++++Class+objects+provide+these+attributes:
++++++++__doc__+++++++++documentation+string
++++++++__module__++++++name+of+module+in+which+this+class+was+defined"""
++++return+isinstance(object,+(type,+types.ClassType))|code-block|syntax|javascript|354464|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

The inspect.isclass is probably the best solution, and it's really easy to see how it's actually implemented

<pre><code>def isclass(object):
 """Return true if the object is a class.

 Class objects provide these attributes:
 __doc__ documentation string
 __module__ name of module in which this class was defined"""
 return isinstance(object, (type, types.ClassType))
</code></pre>

blocks|key|3136779|text|isinstance(X,+type)|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|3136780|如果X是类，则返回True；如果不是，则返回False。|unstyled|offset|length|style|CODE|3136781|entityMap^0|0|2|1|9|4|M|5|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|N|8|@$G|O|H|P|I|J]|$G|Q|H|R|I|J]|$G|S|H|T|I|J]]|9|@]|A|$]]|$1|K|3|-4|5|F|7|U|8|@]|9|@]|A|$]]]|L|$]]

<pre><code>isinstance(X, type)
</code></pre>

Return <code>True</code> if <code>X</code> is class and <code>False</code> if not.

blocks|key|3136803|text|此检查与Python+2.x和Python+3.x都兼容。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3136804|import+six
isinstance(obj,+six.class_types)|code-block|syntax|javascript|3136805|这基本上是一个包装器函数，它执行与andrea_crotti+answer中相同的检查。|3136806|示例：|3136807|>>>+import+datetime
>>>+isinstance(datetime.date,+six.class_types)
>>>+True
>>>+isinstance(datetime.date.min,+six.class_types)
>>>+False|3136808|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|D|7|S|8|@]|9|@]|A|$E|F]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

This check is compatible with both Python 2.x and Python 3.x. 

<pre><code>import six
isinstance(obj, six.class_types)
</code></pre>

This is basically a wrapper function that performs the same check as in andrea_crotti answer.

Example:

<pre><code>&gt;&gt;&gt; import datetime
&gt;&gt;&gt; isinstance(datetime.date, six.class_types)
&gt;&gt;&gt; True
&gt;&gt;&gt; isinstance(datetime.date.min, six.class_types)
&gt;&gt;&gt; False
</code></pre>

blocks|key|353301|text|本杰明·彼得森在这项工作中使用inspect.isclass()是正确的。但请注意，您可以使用内置函数issubclass测试Class对象是否是特定的Class，从而隐式地测试Class。根据您的用例，这可能更具pythonic风格。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|353302|from+typing+import+Type,+Any
def+isclass(cl:+Type[Any]):
++++try:
++++++++return+issubclass(cl,+cl)
++++except+TypeError:
++++++++return+False|code-block|syntax|javascript|353303|然后可以像这样使用：|353304|>>>+class+X():
...+++++pass
...+
>>>+isclass(X)
True
>>>+isclass(X())
False|353305|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.python.org/3/library/functions.html#issubclass^0|F|H|1R|5|24|5|2H|5|1F|A|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]|$9|11|A|12|B|C]|$9|13|A|14|B|C]]|D|@$9|15|A|16|1|17]]|E|$]]|$1|F|3|G|5|H|7|18|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|19|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|1A|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|1B|8|@]|D|@]|E|$]]]|P|$Q|$5|R|S|T|E|$U|V]]]]

Benjamin Peterson is correct about the use of <code>inspect.isclass()</code> for this job.
But note that you can test if a <code>Class</code> object is a specific <code>Class</code>, and therefore implicitly a <code>Class</code>, using the built-in function <a href="https://docs.python.org/3/library/functions.html#issubclass" rel="nofollow noreferrer">issubclass</a>.
Depending on your use-case this can be more pythonic.

<pre><code>from typing import Type, Any
def isclass(cl: Type[Any]):
 try:
 return issubclass(cl, cl)
 except TypeError:
 return False
</code></pre>

Can then be used like this:

<pre><code>&gt;&gt;&gt; class X():
... pass
... 
&gt;&gt;&gt; isclass(X)
True
&gt;&gt;&gt; isclass(X())
False
</code></pre>

blocks|key|353278|text|类Foo:被称为旧式类，类X(object)：被称为新式类。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|353279|检查此What+is+the+difference+between+old+style+and+new+style+classes+in+Python?。推荐使用新样式。阅读关于"unifying+types+and+classes“的文章|offset|length|353280|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/54867/old-style-and-new-style-classes-in-python|1|http://www.python.org/download/releases/2.2.3/descrintro/^0|0|3|21|0|2I|Q|1|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Q|8|@]|9|@$D|R|E|S|1|T]|$D|U|E|V|1|W]]|A|$]]|$1|F|3|-4|5|6|7|X|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]|N|$5|I|J|K|A|$L|O]]]]

class Foo: is called old style class and class X(object): is called new style class. 

Check this <a href="https://stackoverflow.com/questions/54867/old-style-and-new-style-classes-in-python">What is the difference between old style and new style classes in Python?</a> . New style is recommended. Read about "<a href="http://www.python.org/download/releases/2.2.3/descrintro/" rel="nofollow noreferrer">unifying types and classes</a>"

blocks|key|357134|text|最简单的方法是使用投票最多的答案中发布的inspect.isclass。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|357135|实现细节可以在python2+inspect和python3+inspect上找到。|357136|对于新风格的类：isinstance(object,+type)|357137|对于旧式类：isinstance(object,+types.ClassType)|357138|em，对于旧式类，它使用types.ClassType，这是来自types.py的代码|357139|class+_C:
++++def+_m(self):+pass
ClassType+=+type(_C)|code-block|syntax|javascript|357140|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/enthought/Python-2.7.3/blob/master/Lib/inspect.py|1|https://github.com/python/cpython/blob/master/Lib/inspect.py|2|https://github.com/enthought/Python-2.7.3/blob/master/Lib/types.py#L51:1^0|K|F|0|7|F|0|N|F|1|0|8|O|0|6|Z|0|C|F|W|8|2|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@$9|15|A|16|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|17|8|@]|D|@$9|18|A|19|1|1A]|$9|1B|A|1C|1|1D]]|E|$]]|$1|H|3|I|5|6|7|1E|8|@$9|1F|A|1G|B|C]]|D|@]|E|$]]|$1|J|3|K|5|6|7|1H|8|@$9|1I|A|1J|B|C]]|D|@]|E|$]]|$1|L|3|M|5|6|7|1K|8|@$9|1L|A|1M|B|C]]|D|@$9|1N|A|1O|1|1P]]|E|$]]|$1|N|3|O|5|P|7|1Q|8|@]|D|@]|E|$Q|R]]|$1|S|3|-4|5|6|7|1R|8|@]|D|@]|E|$]]]|T|$U|$5|V|W|X|E|$Y|Z]]|10|$5|V|W|X|E|$Y|11]]|12|$5|V|W|X|E|$Y|13]]]]

simplest way is to use <code>inspect.isclass</code> as posted in the most-voted answer. 
the implementation details could be found at <a href="https://github.com/enthought/Python-2.7.3/blob/master/Lib/inspect.py" rel="nofollow noreferrer">python2 inspect</a> and <a href="https://github.com/python/cpython/blob/master/Lib/inspect.py" rel="nofollow noreferrer">python3 inspect</a>. 
for new-style class: <code>isinstance(object, type)</code> 
for old-style class: <code>isinstance(object, types.ClassType)</code> 
em, for old-style class, it is using <code>types.ClassType</code>, here is the code from <a href="https://github.com/enthought/Python-2.7.3/blob/master/Lib/types.py#L51:1" rel="nofollow noreferrer">types.py</a>:

<pre><code>class _C:
 def _m(self): pass
ClassType = type(_C)
</code></pre>

blocks|key|357147|text|有一种替代方法可以检查它：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|357148|import+inspect

class+cls():
+++++print(None)

inspect.isclass(cls)|code-block|syntax|javascript|357149|参考：https://www.kite.com/python/docs/inspect.isclass|offset|length|357150|entityMap|0|LINK|mutability|MUTABLE|url|https://www.kite.com/python/docs/inspect.isclass^0|0|0|3|1C|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

There is an alternative way to check it:
<pre><code>import inspect

class cls():
 print(None)

inspect.isclass(cls)
</code></pre>
Reference: <a href="https://www.kite.com/python/docs/inspect.isclass" rel="nofollow noreferrer">https://www.kite.com/python/docs/inspect.isclass</a>

blocks|key|3349658|text|嗯，inspect.isclass不适合我，相反，试试这个|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3349659|class+foo:
++++pass

var+=+foo()

if+str(type(var)).split(".")[0]+==+"<class+'__main__":
++++print("this+is+a+class")
else:
++++print(str(type(var)).split(".")[0])|code-block|syntax|javascript|3349660|所以基本上，type(var)就是<class+'a+type'>|3349661|示例：<class+'int'但是，当var是一个类时，它将类似于<class+'__main__.classname'>|3349662|因此，我们将字符串拆分成<class+'__main__，并使用if进行比较，如果字符串完全符合，则它是一个类|3349663|​|3349664|📷|atomic|3349665|3349666|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/272db621e95381de4c4d6ce324adc2d4.png|imageAlt^0|2|F|0|0|6|9|H|G|0|3|C|J|3|X|S|0|C|G|W|2|0|0|0|1|0|0|0^^$0|@$1|2|3|4|5|6|7|15|8|@$9|16|A|17|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|18|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|19|8|@$9|1A|A|1B|B|C]|$9|1C|A|1D|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|1E|8|@$9|1F|A|1G|B|C]|$9|1H|A|1I|B|C]|$9|1J|A|1K|B|C]]|D|@]|E|$]]|$1|O|3|P|5|6|7|1L|8|@$9|1M|A|1N|B|C]|$9|1O|A|1P|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|6|7|1Q|8|@]|D|@]|E|$]]|$1|S|3|T|5|U|7|1R|8|@]|D|@$9|1S|A|1T|1|1U]]|E|$]]|$1|V|3|R|5|6|7|1V|8|@]|D|@]|E|$]]|$1|W|3|-4|5|6|7|1W|8|@]|D|@]|E|$]]]|X|$Y|$5|Z|10|11|E|$12|13|14|-4]]]]

Well, <code>inspect.isclass</code> is not working for me, instead, try this
<pre class="lang-py prettyprint-override"><code>class foo:
 pass

var = foo()

if str(type(var)).split(&quot;.&quot;)[0] == &quot;&lt;class '__main__&quot;:
 print(&quot;this is a class&quot;)
else:
 print(str(type(var)).split(&quot;.&quot;)[0])
</code></pre>
So basically, <code>type(var)</code> is <code>&lt;class 'a type'&gt;</code>
Example: <code>&lt;class 'int'</code>
But, when <code>var</code> is a class, it will appear something like <code>&lt;class '__main__.classname'&gt;</code>
So we split the string into <code>&lt;class '__main__</code> and we compare using <code>if</code>, if the string fit perfectly then it's a class
<a href="https://i.stack.imgur.com/Ey0ll.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Ey0ll.png" alt="enter image description here" /></a>

blocks|key|3136847|text|在某些情况下(取决于您的系统)，一个简单的测试是查看您的变量是否具有__module__属性。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3136848|if+getattr(my_variable,'__module__',+None):
++++print(my_variable,+".__module__+is+",my_variable.__module__)
else:
++++print(my_variable,'+has+no+__module__.')|code-block|syntax|javascript|3136849|int、float、dict、list、str等没有__module__|3136850|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

In some cases (depending on your system), a simple test is to see if your variable has a __module__ attribute.
<pre><code>if getattr(my_variable,'__module__', None):
 print(my_variable, &quot;.__module__ is &quot;,my_variable.__module__)
else:
 print(my_variable,' has no __module__.')
</code></pre>
int, float, dict, list, str etc do not have __module__

blocks|key|3349615|text|这里已经有了一些有效的解决方案，但这里有另一个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3349616|>>>+import+types
>>>+class+Dummy:+pass
>>>+type(Dummy)+is+types.ClassType
True|code-block|syntax|javascript|3349617|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

There are some working solutions here already, but here's another one:

<pre><code>&gt;&gt;&gt; import types
&gt;&gt;&gt; class Dummy: pass
&gt;&gt;&gt; type(Dummy) is types.ClassType
True
</code></pre>

I was wondering how to check whether a variable is a class (not an instance!) or not.

I've tried to use the function <code>isinstance(object, class_or_type_or_tuple)</code> to do this, but I don't know what type would a class will have.

For example, in the following code

<pre><code>class Foo: pass 
isinstance(Foo, **???**) # i want to make this return True.
</code></pre>

I tried to substitute "<code>class</code>" with ???, but I realized that <code>class</code> is a keyword in python.

How to check whether a variable is a class or not?

我想知道如何检查变量是否是类(而不是实例！)或者不是。我曾尝试使用函数isinstance(object, class_or_type_or_tuple)来完成此操作，但我不知道一个类将具有什么类型。例如，在下面的代码中class Foo: pass  isinstance(Foo, **???**) # i want to make this return True.我尝试将"class“替换为

问如何检查变量是否为类？
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回答 12

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问如何检查变量是否为类？EN

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问如何检查变量是否为类？
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