August 9, 2019 reflected

Reflection / introspection: program can access, modify the ability to detect and the state itself or behavior.

python, offers four functions:

hasattr (obj, name) whether obj method does not have a corresponding string or attribute name

getattr (obj, name (, default)) until the value in the name of obj

When setattr (obj, name, value) in the name of the set value value obj

delattr (obj, name) delete the name value in the obj

class BlackMedium:
    feture='ugly'
    def __init__(self,name1,addr):
        self.name=name1
        self.addr=addr

    def sell_hourse(self):
        print('%s正在卖房'%self.name)

    def rent_hourse(self):
        print('%s租房子'%self.name)


b1=BlackMedium('zyk','sh')
r= the hasattr (b1, ' name ' )
 Print (R & lt) 
S = the hasattr (b1, ' sell_hourse ' ) # query b1 can call attribute class BlackMedium in 
Print (S) 
W1 = getattr (b1, ' name ' ) # with b1.name 
w2 of getattr = (B1, ' rent_hourse ' ) # no default parameters if no error will 
W3 = getattr (B1, ' ABC ' , ' do not have this property ' ) # If not, the default parameters feedback 
Print ( W1, W2, W3) # W2 is a function of address
w2 of () 

b1.sb = True # vertical two methods can be used, provided the modified functionality 
setattr (B1, ' SB2 ' , False)
 Print (B1. the __dict__ )
 del b1.sb 
delattr (B1, ' SB2 ' ) # delete 
Print (b1. __dict__ )

》》》

True
True
Zyk <Method BlackMedium.rent_hourse of bound <__ __ BlackMedium main AT 0x102097dd8 >> Object no such property.
Zyk renting
{ 'name': 'zyk' , 'addr': 'sh', 'sb': True, 'sb2 ': False}
{' name ':' Zyk ',' addr ':' SH '}