Python - Classes and OOP(Subclassing)

Learning Python
(Oreilly & Associates Inc)
Mark Lutz (著)
(邦訳版)

開発環境

• OS X Mavericks - Apple(OS)
• Emacs (CUI)、BBEdit - Bare Bones Software, Inc. (GUI) (Text Editor)
• Python (プログラミング言語)

Learning Python (Mark Lutz (著)、Oreilly & Associates Inc)のPART Ⅵ.(Classes and OOP)、CHAPTER 32(Advanced Class Topics)、Test Your Knowledge: Part VI Exercises 3.(Subclassing)を解いてみる。

その他参考書籍

• Pythonチュートリアル 第2版
• Python クックブック 第2版 (原書(最新版))

3.(Subclassing)

コード(BBEdit)

sample.py

#!/usr/bin/env python3
#-*- coding: utf-8 -*-

class MyList:
    def __init__(self, data=[]):
        self.data = list(data)
    def __add__(self, other):
        if isinstance(other, MyList):
            other = other.data
        return MyList(self.data + other)
    def __radd__(self, other):
        return MyList(other + self.data)
    def __getitem__(self, i):
        return self.data[i]
    def append(self, other):
        self.data.append(other)
    def sort(self,key=None, reverse=False):
        self.data.sort(key=key, reverse=reverse)
    def __getattr__(self, name):
        return getattr(self.data, name)
    def __repr__(self):
        return 'MyList: {0}'.format(self.data)

class MyListSub(MyList):
    count = 0
    def __init__(self, data=[]):
        self.count = 0
        MyList.__init__(self, data)
    def __add__(self, other):
        print('+ overloaded operation: {0}'.format(other))
        MyListSub.count += 1
        self.count += 1
        return MyList.__add__(self, other)
    def counter(self):
        print('class: {0}, instance: {1}'.format(MyListSub.count, self.count))
        
if __name__ == '__main__':
    o0 = MyListSub()
    o1 = MyListSub([1])
    o2 = MyListSub([2,3])
    lists = [o0, o1, o2]
    new_lists = []
    for o in lists:
        print(o0 + o)
        o0.counter()
        o.counter()
    for o in lists:
        o.counter()

入出力結果(Terminal)

$ ./sample.py
+ overloaded operation: MyList: []
MyList: []
class: 1, instance: 1
class: 1, instance: 1
+ overloaded operation: MyList: [1]
MyList: [1]
class: 2, instance: 2
class: 2, instance: 0
+ overloaded operation: MyList: [2, 3]
MyList: [2, 3]
class: 3, instance: 3
class: 3, instance: 0
class: 3, instance: 3
class: 3, instance: 0
class: 3, instance: 0
$