Python Learning Notes--some common BIF

1 #Some common examples of BIF and usages2 3 #-------------------------------------------------------------------4 #Issubclass Determine if a class is a subclass of another class5 #Issubclass (class,classinfo) ClassInfo can be a tuple of class objects, as long as the class is a subclass of any of the candidate classes, and returns True6 classA:7     Pass8 classB (A):9     PassTen classC: One     Pass A  - Print("whether B is a subclass of a:", Issubclass (B,a))#True - Print("B is a subclass of B:", Issubclass (B,B))#Note: It returns true, that B is a subclass of B the Print("whether B is a subclass of C:", Issubclass (B,C))#False - Print("B is the subclass of a class in a, B, C:", Issubclass (B, (a,b,c)))#True - #------------------------------------------------------------------- -  + #------------------------------------------------------------------- - #Isinstance Determines whether an object is a certain type + #isinstance (Object,classinfo) #第一个参数是实例对象, the second parameter is a tuple of classes or a bunch of class objects A classA: at     Pass - classB (A): -     Pass - classC: -     Pass -  inb =B () - Print("B is a type a:", Isinstance (B,a))#True to Print("b Whether it is of type B:", Isinstance (B,B))#True + Print("whether B is of type C:", Isinstance (B,C))#False - Print("B is one of the types in a, B, C:", Isinstance (b, (a,b,c)))#True the Print("Intentional Error:", Isinstance (B, (a,b,c)))#The first parameter here will always return FALSE if it is not an instance object * #------------------------------------------------------------------- $ Panax Notoginseng #------------------------------------------------------------------- - #hasattr (Object,name) Whether there is a property, name is a string the #getattr (Object,name[,default]) Gets the property, default is a string, and returns when the fetch fails + #setattr (object,name,value) Setting Properties A #delattr (object,name) Delete property the classA: +     def __init__(Self, x=1): -self.x =x $A =A () $ ifHasattr (A,"x"): -     Print("have a") - Print(GetAttr (A,"y","I'm sorry, no y this property")) theSetAttr (A,"y", 10) - Print(A.Y)WuyiDelattr (A,"y") the #------------------------------------------------------------------- -  Wu #------------------------------------------------------------------- - #property uses an object that invokes the function, and the function sets the value of the object's properties.  About #Property (Fget=none,fset=none,fdel=none,doc=none) $ classTest: -  -     def __init__(self,size = 1,count = 2): -Self.size =size ASelf.count =Count +  the     defGetSize (self): -         returnself.size $     defsetSize (self,value): theSelf.size =value the     defdelsize (selfcount): the         delself.size the  -     defGetCount (self): in         returnSelf.count the     defSetCount (self,value): theSelf.count =value About     defDelcount (self): the         delSelf.count the  theA =Property (Getsize,setsize,delsize) +b =Property (Getcount,setcount,delcount) -  theTest =Test ()Bayi Print(test.size)#1 theTEST.A = 100 the Print(test.size)# - - Print(TEST.A)# - -  the Print(Test.count)#2 thetest.b = 200 the Print(Test.count)# $ the Print(test.b)# $ -  the  the #-------------------------------------------------------------------

Python Learning Notes--some common BIF