python入门-类(二）

1 关于类的导入

可以把类封装到1个文件中

1个文件中也可以封装多个类

在导入的时候可以导入单个，也可以导入多个类，也可以全部导入类

car.py

"""一个可以用于表示汽车的类"""
class Car():
    """一次模拟汽车的简单尝试"""
    def __init__(self,make,model,year):
        """初始化属性"""
        self.make = make
        self.model = model
        self.year = year
        self.odometer_reading = 0


    def get_descriptive_name(self):
        """返回整洁的描述性信息"""
        long_name = str(self.year) + " " + self.make + '' + self.model
        return long_name.title()

    def read_odometer(self):
        """打印汽车里程的信息"""
        print("This car has " + str(self.odometer_reading) + "miles on it")

    def update_odometer(self,mileage):
        self.odometer_reading = mileage

    def increment_odometer(self,miles):
        self.odometer_reading += miles


class ElectricCar(Car):
    """电动汽车的独特之处"""

    def __init__(self, make, model,year):
        """初始化父类的属性"""
        super().__init__(make,model,year)
        self.battery_size = 70

    def describe_battery(self):
        print("This car has a " + str(self.battery_size) +"-kwh battery.")

    def fill_gas_tank(self):
        print("This is OK!")

class Battery():
    def __init__(self,battery_size=70):
        """初始化电瓶的属性"""
        self.battery_size = battery_size

    def describe_battery(self):
        """打印一天描述电瓶容量的消息"""
        print("This car has a " +str(self.battery_size) + "-kwh battery.")

    def get_range(self):
        if self.battery_size == 70:
            range = 240
        elif self.battery_size == 85:
            range = 270

        message = "This car can go approximately " + str(range)
        message +=" miles on a full charge"
        print(message)

import car   导入整个模块

from car import * 导入所有的类

对于互相依赖的类，导入的时候记得 前后顺序

2 PYTHON标准库

OrderedDict 可以记录 字典的 键值添加顺序

from collections import OrderedDict

favorite_languages = OrderedDict()

favorite_languages['jen'] = 'python'
favorite_languages['sarah'] = 'c'
favorite_languages['edward'] = 'ruby'
favorite_languages['phil'] = 'python'

for name,language in favorite_languages.items():
    print(name.title() + "'s favorite language is " + language.title() + ".")

3  关于编写类的编码风格

类的命名 使用驼峰风格  实例和模块名使用小写并且单词之间加下划线

关于空行也要谨慎使用