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月份：2020年4月

Python3面向对象

Posted on | By creatapd

一、什么是面向对象 一个面向对象的例子

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class Document():
    def __init__(self, title, author, context):
        print('init function called')
        self.title = title
        self.author = author
        self.__context = context # __开头的属性是私有属性
 
    def get_context_length(self):
        return len(self.__context)
 
    def intercept_context(self, length):
        self.__context = self.__context[:length]
 
 
harry_potter_book = Document('Harry Potter', 'J. K. Rowling', '... Forever Do not believe any thing is capable of thinking independently ...')
 
 
print(harry_potter_book.title)
print(harry_potter_book.author)
print(harry_potter_book.get_context_length())
 
 
harry_potter_book.intercept_context(10)
 
 
print(harry_potter_book.get_context_length())
 
 
print(harry_potter_book.__context)
 
 
########## 输出 ##########
 
 
init function called
Harry Potter
J. K. Rowling
77
10
 
 
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-5-b4d048d75003> in <module>()
     22 print(harry_potter_book.get_context_length())
     23
---> 24 print(harry_potter_book.__context)
 
 
AttributeError: 'Document' object has no attribute '__context'

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