python3 类的特殊方法

init 初始化函数

repr

del

dir:返回所有的属性

dict:所有的属性

getattribute

coding: utf-8

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疯狂Java联盟">网站: <a href="http://www.crazyit.org">疯狂Java联盟</a>

author yeeku.H.lee kongyeeku@163.com

version 1.0

Copyright (C), 2001-2018, yeeku.H.Lee

This program is protected by copyright laws.

Program Name: Date:

######################################################################### class Rectangle: def init (self, width, height): self.width = width self.height = height def setattr(self, name, value): print('----设置%s属性----' % name) if name == 'size': self.width, self.height = value else: self.dict[name] = value def getattr(self, name): print('----读取%s属性----' % name) if name == 'size': return self.width, self.height else: raise AttributeError def delattr(self, name): print('----删除%s属性----' % name) if name == 'size': self.dict['width'] = 0 self.dict['height'] = 0

rect = Rectangle(3, 4) print(rect.size) rect.size = 6, 8 print(rect.width) del rect.size print(rect.size)

自带的函数：hasattr setattr getattr

call

len getitem setitem

coding: utf-8

def check_key (key): ''' 该函数将会负责检查序列的索引，该索引必须是整数值，否则引发TypeError 且程序要求索引必须为非负整数，否则引发IndexError ''' if not isinstance(key, int): raise TypeError('索引值必须是整数') if key < 0: raise IndexError('索引值必须是非负整数') if key >= 26 ** 3: raise IndexError('索引值不能超过%d' % 26 ** 3) class StringSeq: def init(self): # 用于存储被修改的数据 self.__changed = {} # 用于存储已删除元素的索引 self.__deleted = [] def len(self): return 26 ** 3 def getitem(self, key): ''' 根据索引获取序列中元素 ''' check_key(key) # 如果在self.__changed中找到已经修改后的数据 if key in self.__changed : return self.__changed[key] # 如果key在self.__deleted中，说明该元素已被删除 if key in self.__deleted : return None # 否则根据计算规则返回序列元素 three = key // (26 * 26) two = ( key - three * 26 * 26) // 26 one = key % 26 return chr(65 three) chr(65 two) chr(65 one) def setitem(self, key, value): ''' 根据索引修改序列中元素 ''' check_key(key) # 将修改的元素以key-value对的形式保存在__changed中 self.__changed[key] = value def delitem(self, key): ''' 根据索引删除序列中元素 ''' check_key(key) # 如果__deleted列表中没有包含被删除key，添加被删除的key if key not in self.__deleted : self.__deleted.append(key) # 如果__changed中包含被删除key，删除它 if key in self.__changed : del self.__changed[key]