1.基本继承图解
1.1实例化一个Contact类的对象c
1.2实例化一个Supplier类的对象s
1.3访问对象的属性
1.4访问对象s的方法
1.5类变量详解
如果从新定义c.all_contacts = "xxxxxx";那么,对象c拥有一个新的属性all_contacts,其值为"xxxxxx"。这个c对象属性的修改,不影响Contact.all_contacts, Supplier.all_contacts, s.all_contacts的值。
注:上述通过对象访问类变量,其实都是访问同一个值,它们都属于Contact.all_contacts;只要Contact.all_contacts不修改,实例化的对象就不会修改。
2上述代码验证
In [1]: class mySubclass(object): #继承的基本语法
...: pass
...: In [2]: class Contact: #父类定义
...: all_contacts = []
...: def __init__(self, name, email):
...: self.name = name
...: self.email = email
...: Contact.all_contacts.append(self)
...: In [3]: class Supplier(Contact): #子类定义,继承了Contact类
...: def order(self, order):
...: print("If this were a real system we would send "
...: "{} order to {} ".format(order, self.name))
...: In [4]: c = Contact("Some Body", "somebody@example.net") In [5]: s = Supplier("Sup Plier", "supplier@example.net") In [6]: c.name
Out[6]: 'Some Body' In [7]: c.email
Out[7]: 'somebody@example.net' In [8]: s.name
Out[8]: 'Sup Plier' In [9]: s.email
Out[9]: 'supplier@example.net' In [10]: c.all_contacts
Out[10]: [<__main__.Contact at 0x1e3f42bbb70>, <__main__.Supplier at 0x1e3f42c1278>] In [11]: c.order("I need plier")
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
<ipython-input-11-728826faab97> in <module>()
----> 1 c.order("I need plier") AttributeError: 'Contact' object has no attribute 'order' In [12]: s.order("I need plier")
If this were a real system we would send I need plier order to Sup Plier In [13]: s.all_contacts
Out[13]: [<__main__.Contact at 0x1e3f42bbb70>, <__main__.Supplier at 0x1e3f42c1278>]
参考:本文参考学习《Python3 Object Oriented Programming》,Dusty Phillips 著