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变量名只能包含字母、 数字和下划线。 变量名可以字母或下划线打头, 但不能以数字打头, 例如, 可将变量命名为message_1, 但不能将其命名为1_message。
变量名不能包含空格, 但可使用下划线来分隔其中的单词。 例如, 变量名greeting_message可行, 但变量名greeting message会引发错误。 不要将Python关键字和函数名用作变量名, 即不要使用Python保留用于特殊用途的单词, 如print (请参见附录A.4) 。 变量名应既简短又具有描述性。 例如, name比n好, student_name比s_n好, name_length比length_of_persons_name好。 慎用小写字母l和大写字母O, 因为它们可能被人错看成数字1和0name="ada lovelace"print(name.upper())print(name.title())print(name.lower())
使用+号拼接即可name="hello"name2="world"print(name+name2)
language = 'python 'print(language)print(language.rstrip())
language = 'python 'print(language)print(language.lstrip())
language = ' python 'print(language)print(language.strip())
age=23print("age="+str(age))
list = ['trek','cannondale','redline','special']print(list)
print(list[0])
list.append("add");print(list[-1])
list.append(1,"insert")print(list[1])
del list[0]print(list[0])
print(list.pop())
print(list.remove("insert"))
cars = ['bmw','toyota','ben']cars.sort();print(cars)
cars = ['bmw','toyota','ben']cars.sort(reverse=True);print(cars)
print(cars.sorted());print(cars);
cars = ['bmw','toyota','ben']cars.reverse();print(cars)
print(cars.len())
magicians = ['alice', 'david', 'carolina']for magician in magicians:print(magician)
for value in range(1,5): print(value)numbers = list(range(1,5))for value in numbers: print(value)
min(list)max(list)sum(list)
players = ['charles', 'martina', 'michael', 'florence', 'eli']print(players[0:3])print(players[:3])print(players[2:])
players = ['charles', 'martina', 'michael', 'florence', 'eli']copyPlayers = players[:]
元组中值固定不能修改,初始化时使用括号
dimensions = (200, 50)print(dimensions[0])print(dimensions[1])
dimensions = (200, 50)for dimension in dimensions:print(dimension)
message = input("please write your name")print(message);
age = int("how old")print(age)
两数相除返回余数
>>>4%31>>>5%32
current_number = 1while current_number <= 5:print(current_number)current_number += 1
prompt = "\nTell me something, and I will repeat it back to you:"prompt += "\nEnter 'quit' to end the program. "active = True while active: message = input(prompt) if message == 'quit': active = False else:print(message)
prompt = "\nPlease enter the name of a city you have visited:"prompt += "\n(Enter 'quit' when you are finished.) "while True: city = input(prompt)if city == 'quit': breakelse: print("I'd love to go to " + city.title() + "!")
current_number = 0while current_number < 10: current_number += 1if current_number % 2 == 0: continueprint(current_number)
# 首先, 创建一个待验证用户列表# 和一个用于存储已验证用户的空列表unconfirmed_users = ['alice', 'brian', 'candace']confirmed_users = []# 验证每个用户, 直到没有未验证用户为止# 将每个经过验证的列表都移到已验证用户列表中while unconfirmed_users: current_user = unconfirmed_users.pop() print("Verifying user: " + current_user.title()) confirmed_users.append(current_user)# 显示所有已验证的用户 print("\nThe following users have been confirmed:")for confirmed_user in confirmed_users: print(confirmed_user.title())
def greet_user(username):"""显示简单的问候语"""print("Hello, " + username.title() + "!")greet_user('jesse')
def describe_pet(pet_name, animal_type='dog'):"""显示宠物的信息"""print("\nI have a " + animal_type + ".")print("My " + animal_type + "'s name is " + pet_name.title() + ".")describe_pet(pet_name='willie'
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)
传入任意数量参数的函数
def make_pizza(*toppings):"""打印顾客点的所有配料"""print(toppings)make_pizza('pepperoni')make_pizza('mushrooms', 'green peppers', 'extra cheese')
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 self.age = agedef 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!")
class Car():"""一次模拟汽车的简单尝试"""def __init__(self, make, model, year): self.make = make self.model = model self.year = year self.odometer_reading = 0def get_descriptive_name(self): long_name = str(self.year) + ' ' + self.make + ' ' + self.modelreturn long_name.title()def read_odometer(self): print("This car has " + str(self.odometer_reading) + " miles on it.")def update_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): self.odometer_reading += milesclass 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) my_tesla = ElectricCar('tesla', 'model s', 2016) print(my_tesla.get_descriptive_name())
class Battery():"""一次模拟电动汽车电瓶的简单尝试"""def __init__(self, battery_size=60): """初始化电瓶的属性""" self.battery_size = battery_sizedef describe_battery(self): """打印一条描述电瓶容量的消息""" print("This car has a " + str(self.battery_size) + "-kWh battery.")def get_range(self): """打印一条描述电瓶续航里程的消息""" 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)class ElectricCar(Car):"""模拟电动汽车的独特之处"""def __init__(self, make, model, year): """ 初始化父类的属性, 再初始化电动汽车特有的属性 """ super().__init__(make, model, year) self.battery = Battery()
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