Learn Python's ABC module (GO)

Http://yansu.org/2013/06/09/learn-Python-abc-module.html

1.ABC module function

Python itself does not provide abstract classes and interface mechanisms, and to implement abstract classes, you can use the ABC module. ABC is the abbreviation for abstract Base class.

2. Class and function ABC in the module. Abcmeta

This is the meta-class used to generate the abstract base class. The classes generated by it can be inherited directly.

FromAbcImport abcmetaclass myabc: __metaclass__ = abcmetamyabc. (tuple Issubclass (tuple myabc) assert  Isinstance ((),  myabc)   

In the above example, a MYABC abstract base class is generated, and then the tuple is transformed into its virtual subclass. Then either Issubclass or isinstance can determine whether a tuple is out of the Myabc class.

In addition, the same functionality can be achieved by means __subclasshook__(subclass) of replication, which must be Classmethod

Class Foo(Object): Def__getitem__(Self,Index): ... Def__len__(Self): ... DefGet_iterator(Self): ReturnIter(Self)Class Myiterable:__metaclass__= Abcmeta @abstractmethod Def__iter__(Self): While False: Yield None DefGet_iterator(Self): Return Self.__iter__() @classmethod Def__subclasshook__(Cls,C): IfClsIs myiterable: if Any ( "__iter__"  in  B.for B in C.< Span class= "PLN" >__mro__):  return true return notimplemented< Span class= "PLN" >myiterable. (foo)        

Abc.abstractmethod (function)

The generator that indicates the abstract method

class C:    __metaclass__ = ABCMeta @abstractmethod def my_abstract_method(self, ...): ...

Abc.abstractproperty ([Fget[,fset[,fdel[,doc]])

Indicates an abstract property

class C:    __metaclass__ = ABCMeta @abstractproperty def my_abstract_property(self): ...

The previous example is just a read-only property, and if it is a read-write property, you can:

class C: __ metaclass__ = abcmeta  Getx (self  ...  def Setx (self, Value):   ...  x = Abstractproperty ( Getx, Setx)        

Learning Python's ABC module (GO)