【Pthon100天学习笔记】Day19 面向对象基础

from abc import ABCMeta, abstractmethod


class Employee(metaclass=ABCMeta):
    """员工(抽象类)"""

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

    @abstractmethod
    def get_salary(self):
        """结算月薪(抽象方法)"""
        pass


class Manager(Employee):
    """部门经理"""

    def get_salary(self):
        return 15000.0


class Programmer(Employee):
    """程序员"""

    def __init__(self, name, working_hour=0):
        self.working_hour = working_hou
        super().__init__(name)

    def get_salary(self):
        return 200.0 * self.working_hou


class Salesman(Employee):
    """销售员"""

    def __init__(self, name, sales=0.0):
        self.sales = sales
        super().__init__(name)

    def get_salary(self):
        return 1800.0 + self.sales * 0.05


class EmployeeFactory:
    """创建员工的工厂（工厂模式 - 通过工厂实现对象使用者和对象之间的解耦合）"""

    @staticmethod
    def create(emp_type, *args, **kwargs):
        """创建员工"""
        all_emp_types = {'M': Manager, 'P': Programmer, 'S': Salesman}
        cls = all_emp_types[emp_type.upper()]
        return cls(*args, **kwargs) if cls else None


def main():
    """主函数"""
    emps = [
        EmployeeFactory.create('M', '曹操'), 
        EmployeeFactory.create('P', '荀彧', 120),
        EmployeeFactory.create('P', '郭嘉', 85), 
        EmployeeFactory.create('S', '典韦', 123000),
    ]
    for emp in emps:
        print(f'{emp.name}: {emp.get_salary():.2f}元')


if __name__ == '__main__':
    main()
类与类之间的关系

is-a关系：继承
has-a关系：关联 / 聚合 / 合成
use-a关系：依赖
例子：扑克游戏。
经验：符号常量总是优于字面常量，枚举类型是定义符号常量的最佳选择
from enum import Enum, unique

import random


@unique
class Suite(Enum):
    """花色"""

    SPADE, HEART, CLUB, DIAMOND = range(4)

    def __lt__(self, other):
        return self.value < other.value


class Card():
    """牌"""

    def __init__(self, suite, face):
        """初始化方法"""
        self.suite = suite
        self.face = face

    def show(self):
        """显示牌面"""
        suites = ['♠︎', '♥︎', '♣︎', '♦︎']
        faces = ['', 'A', '2', '3', '4', '5', '6', '7', '8', '9', '10', 'J', 'Q', 'K']
        return f'{suites[self.suite.value]}{faces[self.face]}'

    def __repr__(self):
        return self.show()


class Poker():
    """扑克"""

    def __init__(self):
        self.index = 0
        self.cards = [Card(suite, face)
                      for suite in Suite
                      for face in range(1, 14)]

    def shuffle(self):
        """洗牌（随机乱序）"""
        random.shuffle(self.cards)
        self.index = 0

    def deal(self):
        """发牌"""
        card = self.cards[self.index]
        self.index += 1
        return card

    @property
    def has_more(self):
        return self.index < len(self.cards)


class Player():
    """玩家"""

    def __init__(self, name):
        self.name = name
        self.cards = []

    def get_one(self, card):
        """摸一张牌"""
        self.cards.append(card)

    def sort(self, comp=lambda card: (card.suite, card.face)):
        """整理手上的牌"""
        self.cards.sort(key=comp)


def main():
    """主函数"""
    poker = Poker()
    poker.shuffle()
    players = [Player('东邪'), Player('西毒'), Player('南帝'), Player('北丐')]
    while poker.has_more:
        for player in players:
                player.get_one(poker.deal())
    for player in players:
        player.sort()
        print(player.name, end=': ')
        print(player.cards)


if __name__ == '__main__':
    main()

typedef struct_object {
    /* 引用计数 */
    int ob_refcnt;
    /* 对象指针 */
    struct_typeobject *ob_type;
} PyObject;
/* 增加引用计数的宏定义 */
#define Py_INCREF(op)   ((op)->ob_refcnt++)
/* 减少引用计数的宏定义 */
#define Py_DECREF(op)  //减少计数
    if (--(op)->ob_refcnt != 0) 
        ; 
    else 
        __Py_Dealloc((PyObject *)(op))

list1 = []
list2 = [] 
list1.append(list2)
list2.append(list1)

class SetOnceMappingMixin:
    """自定义混入类"""
    __slots__ = ()

    def __setitem__(self, key, value):
        if key in self:
            raise KeyError(str(key) + ' already set')
        return super().__setitem__(key, value)


class SetOnceDict(SetOnceMappingMixin, dict):
    """自定义字典"""
    pass


my_dict= SetOnceDict()
try:
    my_dict['username'] = 'jackfrued'
    my_dict['username'] = 'hellokitty'
except KeyError:
    pass
print(my_dict)

import threading


class SingletonMeta(type):
    """自定义元类"""

    def __init__(cls, *args, **kwargs):
        cls.__instance = None
        cls.__lock = threading.RLock()
        super().__init__(*args, **kwargs)

    def __call__(cls, *args, **kwargs):
        if cls.__instance is None:
            with cls.__lock:
                if cls.__instance is None:
                    cls.__instance = super().__call__(*args, **kwargs)
        return cls.__instance


class President(metaclass=SingletonMeta):
    """总统(单例类)"""
    
    pass

class StreamHasher():
    """哈希摘要生成器"""

    def __init__(self, alg='md5', size=4096):
        self.size = size
        alg = alg.lower()
        self.hasher = getattr(__import__('hashlib'), alg.lower())()

    def __call__(self, stream):
        return self.to_digest(stream)

    def to_digest(self, stream):
        """生成十六进制形式的摘要"""
        for buf in iter(lambda: stream.read(self.size), b''):
            self.hasher.update(buf)
        return self.hasher.hexdigest()

def main():
    """主函数"""
    hasher1 = StreamHasher()
    with open('Python-3.7.6.tgz', 'rb') as stream:
        print(hasher1.to_digest(stream))
    hasher2 = StreamHasher('sha1')
    with open('Python-3.7.6.tgz', 'rb') as stream:
        print(hasher2(stream))


if __name__ == '__main__':
    main()