September 29, 2019 custom property

Descriptor underlying method can be realized most pyhon class characteristics, comprising: classmethod, staticmethd, property, __slots__

Descriptor is modified to define a class attribute class

class Lazyproperty:
     DEF  the __init__ (Self, FUNC):
         Print ( ' >>>>> ' , FUNC) 
        self.func = FUNC
     DEF  __get__ (Self, instance, owner): # Self is Lazyproperty () generated object 
        Print ( ' get method ' )
         return self.func (instance) # instance meaning examples of delivery itself, owner class instance is generated 




class Room:
     # descriptor is modified to define the class 
    # Area = Lazyproperty (Area) # descriptor operation, but the following @lazyproperty is doing the same thing 
    DEF  __init__(Self, name, width, length): 
        self.name = name 
        self.width = width 
        self.length = length 

    # the @Property # @ static properties have actually run in the area = property (area) equivalent to property do instantiation . May be a function, or may be based, is able to achieve decorative effects, achieve increased to the class descriptor Property = Area (Area) 
    @Lazyproperty
     DEF Area (Self):
         return self.width * self.length 




R1 = Room ( ' CS ' , 2,4 )
 Print (r1.area) # where the call is Lazyproperty (area) returns the assigned area, the non-trigger data descriptor 
# Print (r1.area.func (R1)) # purely manual trigger run

》》》》》》》》》》

get method
8