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copied!<p>Maybe a bit of example code will help: Notice the difference in the call signatures of <code>foo</code>, <code>class_foo</code> and <code>static_foo</code>:</p> <pre><code>class A(object): def foo(self,x): print "executing foo(%s,%s)"%(self,x) @classmethod def class_foo(cls,x): print "executing class_foo(%s,%s)"%(cls,x) @staticmethod def static_foo(x): print "executing static_foo(%s)"%x a=A() </code></pre> <p>Below is the usual way an object instance calls a method. The object instance, <code>a</code>, is implicitly passed as the first argument.</p> <pre><code>a.foo(1) # executing foo(<__main__.A object at 0xb7dbef0c>,1) </code></pre> <hr> <p><strong>With classmethods</strong>, the class of the object instance is implicitly passed as the first argument instead of <code>self</code>.</p> <pre><code>a.class_foo(1) # executing class_foo(<class '__main__.A'>,1) </code></pre> <p>You can also call <code>class_foo</code> using the class. In fact, if you define something to be a classmethod, it is probably because you intend to call it from the class rather than from a class instance. <code>A.foo(1)</code> would have raised a TypeError, but <code>A.class_foo(1)</code> works just fine:</p> <pre><code>A.class_foo(1) # executing class_foo(<class '__main__.A'>,1) </code></pre> <p>One use people have found for class methods is to create <a href="https://stackoverflow.com/a/1950927/190597">inheritable alternative constructors</a>.</p> <hr> <p><strong>With staticmethods</strong>, neither <code>self</code> (the object instance) nor <code>cls</code> (the class) is implicitly passed as the first argument. They behave like plain functions except that you can call them from an instance or the class:</p> <pre><code>a.static_foo(1) # executing static_foo(1) A.static_foo('hi') # executing static_foo(hi) </code></pre> <p>Staticmethods are used to group functions which have some logical connection with a class to the class.</p> <hr> <p><code>foo</code> is just a function, but when you call <code>a.foo</code> you don't just get the function, you get a "partially applied" version of the function with the object instance <code>a</code> bound as the first argument to the function. <code>foo</code> expects 2 arguments, while <code>a.foo</code> only expects 1 argument.</p> <p><code>a</code> is bound to <code>foo</code>. That is what is meant by the term "bound" below:</p> <pre><code>print(a.foo) # <bound method A.foo of <__main__.A object at 0xb7d52f0c>> </code></pre> <p>With <code>a.class_foo</code>, <code>a</code> is not bound to <code>class_foo</code>, rather the class <code>A</code> is bound to <code>class_foo</code>.</p> <pre><code>print(a.class_foo) # <bound method type.class_foo of <class '__main__.A'>> </code></pre> <p>Here, with a staticmethod, even though it is a method, <code>a.static_foo</code> just returns a good 'ole function with no arguments bound. <code>static_foo</code> expects 1 argument, and <code>a.static_foo</code> expects 1 argument too.</p> <pre><code>print(a.static_foo) # <function static_foo at 0xb7d479cc> </code></pre> <p>And of course the same thing happens when you call <code>static_foo</code> with the class <code>A</code> instead.</p> <pre><code>print(A.static_foo) # <function static_foo at 0xb7d479cc> </code></pre>

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