python类和对象的一些方法（GIF）

1.类和对象的一些GIF

1.1issubclass(类1，类2)

若类1 是类2 的子类，返回True；

>>> class a: pass >>> class b(a): pass >>> issubclass(b,a) True >>> issunclass(b,b) >>> issubclass(b,b) True

1.2 isinstance(对象，类)

若对象是类的实例化对象，返回True；

>>> class a: pass >>> class b(a): pass >>> b1 = b() >>> isinstance(b1,b) True >>> class c: pass >>> isinstance(b1,(a,b,c)) True

1.3 hasattr(对象，属性)

若该对象有此属性返回True

>>> class c: def __init__(self,x=0): self.x = x >>> c1=c() >>> hasattr(c1,'x') True >>> hasattr(c1,x) Traceback (most recent call last): File "<pyshell#26>", line 1, in <module> hasattr(c1,x) NameError: name 'x' is not defined

1.4 getattr(对象，属性[，default])

不解释

>>> class c: def __init__(self,x=0): self.x = x >>> c1=c() >>> getattr(c1,'x') 0 >>> getattr(c1,'y',"你所访问的属性不存在....") '你所访问的属性不存在....' >>>

1.5 setattr(object,name,value)

给对象赋予属性name，并附上值value;

>>> setattr(c1,'y','你莫不是想什么呢') >>> getattr(c1,'y',"你所访问的属性不存在....") '你莫不是想什么呢'

1.6 delattr(object,name)

删除object中的属性name；

>>> delattr(c1,'y') >>> delattr(c1,'y') Traceback (most recent call last): File "<pyshell#33>", line 1, in <module> delattr(c1,'y') AttributeError: y >>>

1.7 property()

class c: def __init__(self,size=10): self.size = size def getsize(self): return self.size def setsize(self,value): self.size = value def delsize(self): del self.size x=property(getsize,setsize,delsize) >>> c1 = c() >>> c1.getsize() 10 >>> c1.x 10 >>> c1.x=18 >>> c1.x 18 >>> c1.size 18 c1.getsize() 18 >>> del c1.x >>> c1.size Traceback (most recent call last): File "<pyshell#11>", line 1, in <module> c1.size AttributeError: 'c' object has no attribute 'size'