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Python3 关于类的学习

Python3 关于类的学习

作者: 半场_64dd | 来源:发表于2018-10-05 19:33 被阅读0次

#!/usr/bin/python3

import _thread

import time

##class Dog():

##        def __init__(self,name,age):

##                self.name = name

##                self.age = age

##        def sit(self):

##                print(self.name.title() + "is now sitting")

##        def roll_over(self):

##                print(self.name.title() + "rolled over!")

##my_dog = Dog('willie',6)

##print("My dog's name is " + my_dog.name )

##

### 为线程定义一个函数

##def print_time( threadName, delay):

##   count = 0

##   while count < 20:

##      time.sleep(delay)

##      count += 1

##      print ("%s: %s\r\n" % ( threadName, time.ctime(time.time()) ))

##

### 创建两个线程

##try:

##   _thread.start_new_thread( print_time, ("Thread-1", 2, ) )

##   _thread.start_new_thread( print_time, ("Thread-2", 2, ) )

##except:

##   print ("Error: 无法启动线程")

##

##while 1:

##   pass

##2018年10月5日13:44:32

#2018年10月5日13:44:32

"""Python关于类(Class)的学习"""

class Dog():

    """一次模拟小狗的简单尝试"""

    def __init__(self,name,age):

        self.name = name

        self.age = age

    def sit(self):

        """模拟小狗被命令时蹲下"""

        print(self.name.title() + " is now sitting.")

    def roll_over(self):

        """模拟小狗被命令时打滚"""

        print(self.name.title() + " rolled over!")

"""根据类创建实例并访问类的属性"""

my_dog = Dog('willie',6)

print("My dog's name is " + my_dog.name.title() + ".")

print("My dog is " + str(my_dog.age) + " years old.")

"""调用方法"""

my_dog.sit()

my_dog.roll_over()

"""动手试一试"""

class Restaurant():

    def __init__(self,restaurant_name,cuisine_type):

        self.resname = restaurant_name

        self.cuistype = cuisine_type

    def describe_restaurant(self):

        print(self.resname + " is the restaurant name.")

        print(self.cuistype + " is the restaurant cuisine_type")

    def open_restaurant(self):

        print("The restaurant is open now")

myrestaurant = Restaurant("Spicy way","Chinese food")

myrestaurant.describe_restaurant()

myrestaurant.open_restaurant()

res1 = Restaurant("Zuoxiangyoulin","XiangCai")

res2 = Restaurant("Aiwanting","XiangCai")

res3 = Restaurant("Lanzhoufood","Lanzhou")

res1.describe_restaurant()

res2.describe_restaurant()

res3.describe_restaurant()

class User():

    def __init__(self,first_name,last_name,age,grade,professional):

        self.first_name = first_name

        self.last_name = last_name

        self.age = age

        self.grade = grade

        self.professional = professional

    def describe_user(self):

        print(self.first_name + " is My First_name.")

        print(self.last_name + " is  My Last_nme.")

        print("My age is " + self.age + ".")

        print("My grade is " + self.grade + ".")

        print(self.professional + " is my job.")

    def great_user(self):

        print("Welcome, "+ self.first_name + self.last_name + " nice to meet you!")

stu1 = User("Pan","Yan","22","Male","Engineer")

stu1.describe_user()

stu1.great_user()

class Car():

    """一次模拟汽车的简单尝试"""

    def __init__(self,make,model,year):

        """初始化描述汽车的属性"""

        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

        ##long_name = self.year + ' ' + self.make + ' ' + self.model

        return long_name.title()

    def read_odometer(self):

        print("This car has "+ str(self.odometer_reading) + " miles on it")

    def updata_odometer(self,mileage):

        if mileage >= self.odometer_reading:

            self.odometer_reading = mileage

        else:

            print("You can't roll back an odometer!")

    def increment_odometer(self,miles):

        if miles >= 0:

            self.odometer_reading += miles

        else:

            print("You can't set an miles with  negative increments")

    def fill_gas_tank(self,gallon):

        print("The car have "+ str(gallon) + ' capacity')

##9.3.5 将实例用作属性

class Battery():

    def __init__(self,battery_size=70):

        self.battery_size = battery_size+10

    def describe_battery(self):

        print("This car has a "+ str(self.battery_size) + "-kWh battery.")

class ElectricCar(Car):

    def __init__(self,make,model,year):

        super().__init__(make,model,year)

        self.battery = Battery()

##    def describe_battery(self):

##        print("This car has a " + str(self.battery_size) + "-kWh battery.")

    def fill_gas_tank(self,gallon):

        print("This car doesn't need a gas tank!")

my_tesla = ElectricCar('tesla','model s',2016)

print(my_tesla.get_descriptive_name())

my_tesla.battery.describe_battery()

my_tesla.fill_gas_tank(20)

my_new_car = Car('andi','a4',2016)

print(my_new_car.get_descriptive_name())

my_new_car.read_odometer()

my_new_car.odometer_reading = 23

my_new_car.read_odometer()

my_new_car.updata_odometer(10)

my_new_car.read_odometer()

my_new_car.increment_odometer(100)

my_new_car.read_odometer()

创建和使用类

           ​class Dog():

###class        关键字

###Dog()ClassName一般首字母大写

                   方法 __init__()

exp: __init__(self,name,age):

### __init__()称为方法,我们将方法__init__() 定义成了包含三个形参:self 、name 和age 。在这个方法的定义中,形参self 必不可少,还必须位于其他形参的前面。为何必须在方法定义中包含形参self 呢?因为Python调用这个__init__() 方法来创建Dog 实例时,将自动传入实参self 。每个与类相关联的方法调用都自动传递实参self ,它是一个指向实例本身的引用,让实例能够访问类中的属性和方法。我们创建Dog 实例时,Python将调用Dog 类的方法__init__() 。我们将通过实参向Dog() 传递名字和年龄;self 会自动传递,因此我们不需要传递它。每当我们根据Dog 类创建实例时,都只需给最后两个形参(name 和age )提供值。

self.name = name

self.age = age

###以self为前缀的变量都可供类中的所有方法使用,我们还可以通过类的任何实例来访问这些变量。可通过实例访问到的变量称为属性

my_dog = Dog('Hole',6)

my_dog.name###要访问实例的属性,可以使用句点表示法。

调用方法

my_dog.sit()

my_dog.roll_over()###实例名称+'.'+方法。

在class Car里面,我们给类中的每个属性制定初始值,

修改属性的值

1.直接修改属性的值。

2.通过方法修改属性的值

继承

​class Car():

class ElectricCar(Car):

    def __init__(self,make,model,year):

         super().__init__(make,model,year)

父类必须位于子类的前面,定义子类时,必须在括号内指定父类名称。

使用super()函数将父类和子类关联起来,

当子类有某个属性与父类不一致时,譬如小汽车和电动汽车,电动汽车没有油箱,我们可以通过重写父类的方法,给子类写一个和父类重名的方法。使子类的该属性值不冲父类处继承。

将实例用作属性

使用代码模拟实物时,属性和方法的文件都越来越长,可以将类的一部分作为一个独立的类提取出来。

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