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copied!<p>Here's the more pragmatic answer.</p> <p><strong>It rarely matters</strong></p> <ol> <li><p>"<a href="https://stackoverflow.com/questions/100003/what-is-a-metaclass-in-python">What is a metaclass in Python</a>". Bottom line, <code>type</code> is the metaclass of all classes. You have almost no practical use for this. </p> <pre><code>class X(object): pass type(X) == type </code></pre></li> <li><p>"<a href="https://stackoverflow.com/questions/392160/what-are-your-concrete-use-cases-for-metaclasses-in-python">What are your (concrete) use cases for metaclasses in Python?</a>". Bottom line. None.</p></li> <li><p>"<a href="http://fuhm.net/super-harmful/" rel="nofollow noreferrer">Python's Super is nifty, but you can't use it</a>". Interesting note, but little practical value. You'll never have a need for resolving complex multiple inheritance networks. It's easy to prevent this problem from arising by using an explicity <strong>Strategy</strong> design instead of multiple inheritance. </p></li> </ol> <p>Here's my experience over the last 7 years of Python programming.</p> <ol> <li><p>A class has 1 or more superclasses forming a simple chain from my class to <code>object</code>.</p></li> <li><p>The concept of "class" is defined by a metaclass named <code>type</code>. I might want to extend the concept of "class", but so far, it's never come up in practice. Not once. <code>type</code> always does the right thing.</p></li> <li><p>Using <code>super</code> works out really well in practice. It allows a subclass to defer to it's superclass. It happens to show up in these metaclass examples because they're extending the built-in metaclass, <code>type</code>. </p> <p>However, in all subclass situations, you'll make use of <code>super</code> to extend a superclass.</p></li> </ol> <p><strong>Metaclasses</strong></p> <p>The metaclass issue is this: </p> <ul> <li><p>Every object has a reference to it's type definition, or "class".</p></li> <li><p>A <code>class</code> is, itself, also an object.</p></li> <li><p>Therefore a object of type <code>class</code> has a reference to it's type or "class". The "class" of a "class" is a metaclass.</p></li> </ul> <p>Since a "class" isn't a C++ run-time object, this doesn't happen in C++. It does happen in Java, Smalltalk and Python.</p> <p>A metaclass defines the behavior of a class object.</p> <ul> <li><p>90% of your interaction with a class is to ask the class to create a new object.</p></li> <li><p>10% of the time, you'll be using class methods or class variables ("static" in C++ or Java parlance.)</p></li> </ul> <p>I have found a few use cases for class-level methods. I have almost no use cases for class variables. I've never had a situation to change the way object construction works.</p>

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