Python - Oh Oh: Objects and Classes(Name Mangling for Privacy, Aggregation and Composition)

Introducing Python
邦訳

開発環境

• OS X El Capitan - Apple (OS)
• Emacs (Text Editor)
• Python 3.5 (プログラミング言語)

Introducing Python: Modern Computing in Simple Packages (Bill Lubanovic (著)、 O'Reilly Media)のChapter 6(Oh Oh: Objects and Classes)、Things to Do 6.1-10.を取り組んでみる。

Things to Do 6.1-10.

コード(Emacs)

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

print('6.1')


class Thing:
    pass

print(Thing)

example = Thing()
print(example)

print('6.2')


class Thing2:
    letters = 'abc'

print(Thing2.letters)

print('6.3')


class Thing3:

    def __init__(self):
        self.letters = 'xyz'

thing3 = Thing3()
print(thing3.letters)

print('6.4')


class Element:

    def __init__(self, name, symbol, number):
        self.name = name
        self.symbol = symbol
        self.number = number

    def dump(self):
        print('name: {0}, symbol: {1}, number: {2}'.format(
            self.name, self.symbol, self.number))

    def __str__(self):
        return 'name: {0}, symbol: {1}, number: {2}'.format(
            self.name, self.symbol, self.number)

hydrogen1 = Element('Hydrogen', 'H', 1)
print(hydrogen1)

print('6.5')
d = dict(name='Hydrogen', symbol='H', number=1)
hydrogen2 = Element(**d)
print(hydrogen2)

print('6.6')
hydrogen1.dump()
hydrogen2.dump()

print('6.7')

print(hydrogen1)
print(hydrogen2)

print('6.8')


class Element:

    def __init__(self, name, symbol, number):
        self.__name = name
        self.__symbol = symbol
        self.__number = number

    @property
    def name(self):
        return self.__name

    @property
    def symbol(self):
        return self.__symbol

    @property
    def number(self):
        return self.__name

    def dump(self):
        print('name: {0}, symbol: {1}, number: {2}'.format(
            self.name, self.symbol, self.number))

    def __str__(self):
        return 'name: {0}, symbol: {1}, number: {2}'.format(
            self.name, self.symbol, self.number)

h = Element('Hydrogen', 'H', 1)
print(h.name, h.symbol, h.number)
try:
    print(h.__name)
except Exception as err:
    print(err)

print(h._Element__name)

print('6.9')


class Bear:

    def eats(self):
        return 'berries'


class Rabbit:

    def eats(self):
        return 'clover'


class Octothorpe:

    def eats(self):
        return 'campers'

bear = Bear()
rabbit = Rabbit()
octothorpe = Octothorpe()
for a in [bear, rabbit, octothorpe]:
    print(a.eats())

print('6.10')


class Laser:

    def does(self):
        return 'disintegrate'


class Claw:

    def does(self):
        return 'crush'


class SmartPhone:

    def does(self):
        return 'ring'


class Robot:

    def __init__(self):
        self.laser = Laser()
        self.claw = Claw()
        self.smartPhone = SmartPhone()

    def does(self):
        for obj in [self.laser, self.claw, self.smartPhone]:
            print(obj.does())


robot = Robot()
robot.does()

入出力結果(Terminal, IPython)

$ ./sample.py
6.1
<class '__main__.Thing'>
<__main__.Thing object at 0x1052af208>
6.2
abc
6.3
xyz
6.4
name: Hydrogen, symbol: H, number: 1
6.5
name: Hydrogen, symbol: H, number: 1
6.6
name: Hydrogen, symbol: H, number: 1
name: Hydrogen, symbol: H, number: 1
6.7
name: Hydrogen, symbol: H, number: 1
name: Hydrogen, symbol: H, number: 1
6.8
Hydrogen H Hydrogen
'Element' object has no attribute '__name'
Hydrogen
6.9
berries
clover
campers
6.10
disintegrate
crush
ring
$