Python学习笔记2

#1.函数 #例1 def greet_user(username): """显示简单的问候语""" print('Hello,' + username.title() + '!') greet_user('Jesse') #例2 def get_formatted_name(first_name,last_name): """返回整洁的姓名""" full_name = first_name + ' ' + last_name return full_name.title() musician = get_formatted_name('jimi','hendrix') print(musician) #例3 def build_person(first_name,last_name): """返回一个字典，其中包含有关一个人的信息""" person = {'first':first_name.title(),'last':last_name.title()} return person musician = build_person('jimi','hendrix') print(musician) #例4 def print_name1(name1,name2): while name1: current_name = name1.pop() print("Printing name1:" + current_name) name2.append(current_name) def show_name2(name2): print("\nPrinting name2:") for name22 in name2: print(name22) name1 = ['iphone','robot','dodecahedron'] name2 = [] print_name1(name1,name2) show_name2(name2) print_name1(name1[:],name2) #向函数传递列表的副本，禁止函数修改列表 #例5 def make_pizza(*toppings): #可传递任意数量的实参 """打印顾客点的所有配料""" print("\nMaking a pizza with the following toppings") for topping in toppings: print("- " + topping) make_pizza('mushroom','green peppers','extra cheese') #例6 def build_profile(first,last,**user_info): #接受任意数量的关键字实参 profile = {} profile['first_name'] = first profile['last_name'] = last for key,value in user_info.items(): profile[key] = value return profile user_profile = build_profile('albert','einstein',location='princeton',field='physics') print(user_profile) #例7 def make_pizza(size,*toppings): """概述要制作的披萨""" print("\nMake a " + str(size) + "-inch pizza with the following toppings:") for topping in toppings: print("- " + topping) #将其保存为pizza.py，且文件pizza.py中除该函数外无其他代码 import pizza #导入模块pizza，可在程序中使用该模块中所有函数 pizza.make_pizza(12,"mushrooms",'extra cheese') from module_name import function_0,functin_1,function_2#导入特定的函数 #例8 from pizza import make_pizza as mp #指定别名mp mp(12,"mushrooms",'extra cheese') #例9 import pizza as p p.make_pizza(12,"mushrooms",'extra cheese') #例10 from pizza import * #导入模块中的所有函数 make_pizza(12,"mushrooms",'extra cheese')

#2.类 #例1 class Dog(): """一次模拟小狗的简单尝试""" def __init__(self,name,age): """初始化属性name和age""" self.name = name #姓名属性 self.age = age   #年龄属性 def sit(self): #方法蹲下 """模拟小狗被命令时蹲下""" print(self.name.title() + "is now sitting.") def roll_over(self): #方法打滚 """模拟小狗被命令时打滚""" print(self.name.title() + " rolled over!") 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.") my_dog.sit() my_dog.roll_over() #例2 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 #添加属性odometer_reading，初始值为0 def get_name(self): """返回信息""" long_name = str(self.year) + ' ' + self.name + ' ' + self.model return long_name.title() def read_odometer(self): """打印汽车里程信息""" print("This car has " + str(self.odometer_reading) + " miles on it") def update_odometer(self,mileage): """将里程表读书设置为指定的值，且禁止往回调""" if mileage >= self.odometer_reading: self.odometer_reading = mileage else: print("You can't roll back an odometer!") def increment_odometer(self,miles): """将里程表增加指定的量""" self.odometer_reading += miles my_usedcar = Car('subaru','outback',2013) print(my_usedcar.get_name()) my_usedcar.update_odometer(23500) my_usedcar.read_odometer() my_usedcar.increment_odometer(100) my_usedcar.read_odometer() #例3 class ElectricCar(Car): #继承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  #添加子类的新属性 def describe_battery(self): #添加子类的新方法 """打印电瓶容量信息""" print("This car has a " + str(self.battery_size) + "-kWh battery.") my_tesla = ElectricCar('tesila','model s',2016) print(my_tesla.get_name()) my_tesla.describe_battery() #例4 #将例2的Car类保存为car.py from car import Car #导入模块car中的类Car my_newcar = Car('audi','a4',2016) print(my_newcar.get_name()) #或者 import car my_newcar = car.Car('audi','a4',2016) print(my_newcar.get_name()) #例5 from collections import OrderedDict #导入OrderedDict类 favorite_languages = OrderedDict()  #创建空的有序字典 favorite_languages['jen'] = 'python' favorite_languages['sarah'] = 'c' favorite_languages['phil'] = 'ruby' for name,language in favorite_languages.items(): print(name.title() + "'s favorite language is " + language.title() + ".")