[Python知识库]python入门学习

? ? ? ?最近开始学习python语言，看了一些视频，选择了《python编程：从入门到实践》这本书。看书跟着学，书前文推荐是每天看一章，但实际做下来，没课的时候一天可以看四章，上课的时候基本一上上半天，所以一天看两章问题不大。

? ? ? 本来打算配合小甲鱼的python视频一起学习，但由于实在没时间所以放弃了。现在学到书的第七章，感觉还不错。

? ? ? 分享一些我的学习笔记和这本书的一些课后习题答案给大家。为自己的学习生活也做一个简单的记录。

? ? ? ? 总的说来，这本书是本非常好的书，对于有C语言基础的人来说学习起来上手会很快很轻松。

常用命令

1. Spyder清屏

• 清除变量

????????在IPython中输入reset命令，得到提示输入y确认即可

• 清空IPthon中的输入历史记录

????????在控制台输入clear即可

????????使用快捷键Ctrl + L

报错汇总

• 1.EOL while scanning string literal
• ????????Print少打了一个双引号/打成了中文双引号
• 2.invalid character in identifier

????????????????意思是：标志符中的无效字符

• ????????if后面的冒号打成了中文输入法下的冒号
• 3.invalid syntax

????????????????语法错误

• ? ? ? ?字典中键值对之间忘记加逗号了
  • 字典嵌套字典时，被嵌套的字典大括号前应为：写成了=。
  • 字典嵌套字典时，被嵌套的字典和字典大括号之间也要有，。
  • 访问字典中某一键值时[]后面加了.。
  • 在函数这一章，如果形参/实参是字符串的话，形参不需要加双引号，实参需要

????????4.f-string expression part cannot include a backslash

????????????????意思是f字符串中不能出现反斜杠

? ? ? ? 5.'function' object is not subscriptable

? ? ? ? ? ? ? ? ??“函数”对象不可下标

? ? ? ? ? ? ? ? ? 出现原因：一是调用自定义函数时要用圆括号（）而不是方括号[ ]。二是自定义函数名不能与已有变量重名

???????PY

第二章学习笔记

1. print(name.title());此时不需要引号

2. print(f"hello,{name.title()}"):注意此时需要引号，并且函数内的东西要用大括号括起来

练习答案

##2-5
name='albert einsetin'
message='a person who never made a mistake never tried anythiing new'
print(name.title())
print(f"{name.title()} once said {message}")
##2-9
fav_num=8
msg="my favorite number is "+str(fav_num)+"."
print(msg)

第三章学习笔记

1.注意if和while后都有一个冒号：

2.true+true=2

3.

??转换为整型，python会截断处理，不会四舍五入。

4.获得类型的信息一般有两种函数：type 和 isinstance

5. Python 中 / 与 // 的区别

在Python中“/”表示浮点数除法，返回浮点结果，也就是结果为浮点数，而“//”在Python中表示整数除法，返回不大于结果的一个最大的整数，意思就是除法结果向下取整。

6.sorted的参数可以没有，也可以有两个。

???????? 例如打印与字母顺序相反的顺序时：print(sorted(travels,reverse=True))

7.但如果是sort的话，只有一个参数

???????? travels.sort(reverse=True)

print(travels)

且注意sorted不能采用这种方法

练习答案

#3-8放眼世界
travels=['newyork','thailand','japan','london','singpore']
print(travels)
print(sorted(travels))
print(travels)
print("按照相反字母顺序打印")
print(sorted(travels,reverse=True))

print("核实一下是否是原来的顺序")
print(travels)
print("反转顺序")
travels.reverse()
print(travels)
print("再次反转")
travels.reverse()
print(travels)
print("使用sort")
travels.sort()
print(travels)
print("sort反顺序")
travels.sort(reverse=True)
print(travels)

第四章 ?操作列表-学习笔记

1.for语句后一定要记得带冒号，不然会报错！

练习答案

#4-1披萨

pizzas=['pianapple','peigen','potato']

for pizza in pizzas:

??? print("i like "+pizza+' pizza')

print("i really love pizza")



#4-2

con_animals=['rabbit','cat','dog']

for animal in con_animals:

??? print('A '+animal+' would make a great pet')

print('Any of these animals would make a great pet')

#4-3数到20

numbers=[num for num in range(1,21)]

print(numbers)



4-4数到一百万

numbers=[]

for num in range(101):

??? numbers.append(num)

print(numbers)

print(min(numbers))



#4-7奇数

numbers=[]

for num in range(1,21,2):

??? numbers.append(num)

??? print(num)



#4-9立方解析

numbers=[]

for num in range(1,11):

??? numbers.append(num**3)

print(numbers)



print("采用立体解析的方法如下")

numbers=[num**3 for num in range(1,11)]

print(numbers)



#4-10切片

con_animals=['rabbit','cat','dog','panda','bird','lion']

print(con_animals[0:3])

print(con_animals[1:5])

print(con_animals[3:])



#4-11你的披萨我的披萨

pizzas=['pianapple','peigen','potato']

friends_pizza=pizzas[:]

pizzas.append('tomato')

friends_pizza.append('banana')

print("My favorite pizzas are:")

for pizza in pizzas[:]:

??? print(pizza)

for pizza in friends_pizza[:]:

??? print(pizza)

#4-13自助餐

foods=('potato','hundu','vegetables','pizza','humberger')

for food in foods:

??? print(food)

foods=('potato','hulatang','buttonsope','pizza','humberger')

for food in foods:

??? print(food)

第五章 if语句

练习

#5-1

car='subaru'

print("Is car == 'subaru'?I predict True")

print(car=='subaru')



#5-5外星人颜色3

alien_color='red'

if alien_color == 'green':

??? print("你得到了五分")

elif alien_color=='yellow':

??? print("你得到了十分")

else:

??? print("你得到了十五分")



#5-6人生的不同阶段

age=1

if age<2:

??? print("这个人是个婴儿")

elif age>2 and age<4:

??? print("这个人是个幼儿")

elif age>4 and age<13:

??? print("这个人是个儿童")

elif age>13 and age<20:

??? print("这个人是个青少年")

elif age>20 and age<65:

??? print("这个人是个成年人")

elif age>65:

??? print("这个人是个老年人")

???

#5-7喜欢的水果

favorite_fruits=['pineapple','dragon','mihoutao']

if 'pineapple' in favorite_fruits:

??? print("you really like pineapple")



#5-8-9以特殊方式跟管理员打招呼

name_list=['admin','acky','boubou','chick','kevin']

name=input()

if name:

??? if name == 'admin':

??????? print("hello admin,would you like to see a status report?")

??? else:

??????? print("hello jaden,thank you for logging in again")

else:

???? print("we need to find some users")

???



#5-10检查用户名

current_users=['admin','acky','boubou','chick','kevin']

new_users=['acky','nelson','kaka','momoco','kenken']

#print("请输入您的用户名：")

#name=input()

for name in new_users:

??? if name in current_users:

??????? print("用户名已被使用")

??? else:

??????? print("用户名未被使用")



#5-11序数

numbers=[1,2,3,4,5,6,7,8,9,10]

for number in numbers:

??? if number == 1:

??????? print(f"{number}st")

??? elif number == 2:

??????? print(f"{number}nd")

??? else:

??????? print(f"{number}th")

第六章 字典

练习

#6-1人

person={'名':'kk',

??????? '姓':'朴',

??????? '年龄':'22',

??????? '居住城市':'上海',

??????? }

print(f"我姓{person['姓']}")



#6-7人们

person_kk={'名':'kk',

??????? '姓':'朴',

??????? '年龄':'22',

??????? '居住城市':'上海',

????????? }

person_cc={'名':'cc',

??????? '姓':'杨',

??????? '年龄':'32',

??????? '居住城市':'北京',

????????? }

person_aa={'名':'aa',

??????? '姓':'r',

??????? '年龄':'27',

??????? '居住城市':'巴黎',

????????? }

people=[person_kk,person_cc,person_aa]

for person in people:

??? print(person)



#6-8宠物

pet_dog={

?? ??????'name':'dog',

???????? 'owner':'cc',

??????? }

pet_cat={

???????? 'name':'cat',

???????? 'owner':'kk',

??????? }

pet_fish={

???????? 'name':'fish',

???????? 'owner':'aa',

??????? }

pets=[pet_dog,pet_cat,pet_fish]

for pet in pets:

??? print(pet)



#6-9喜欢的地方（字典中嵌套列表）

favorite_places={

????????????????? 'kk':['london','tokyo','korea'],

????????????????? 'aa':['paris','nepol','africa'],

????????????????? 'cc':['shangahai','kaifeng','hangzhou'],

??????????????? }

for name,places in favorite_places.items():

??? print(f"{name.title()}'s favorite places are:")

??? for place in places:

??????? print(place.title())



#6-11 城市（字典嵌套字典）

cities={

??????? 'shanghai':{

??????????????????? 'country':'china',

??????????????????? 'population':'1kw',

??????????????????? 'fact':'beauty',

??????????????????? },

??????? 'tokyo':{

??????????????? 'country':'japan',

??????????????? 'population':'50w',

??????????????? 'fact':'far',

??????????????? },

??????? 'london':{

???????????????? 'country':'england',

???????????????? 'population':'100w',

???????????????? 'fact':'wet',

???????????????? },

???????

???? ???}

for city_name,city_info in cities.items():

??? print(f"city's name is {city_name.title()}")

??? print(f"他属于{city_info['country']}")

??? print(f"它拥有人口{city_info['population']}")

??? print(f"它最大的特点是{city_info['fact']}")

??? 第七章 用户输入和while循环

练习

#7-1汽车租赁

car=input("let me see if i can find you subaru? ")

print(car)



#7-2餐馆定位

number=input('有多少人来吃饭？ ')

number=int(number)

if number >8:

??? print("没有空桌")

else:

??? print("有空座")

#7-4披萨配料

prompt="\n please input a series of pizzas adding"

prompt += '\n(Enter the quit when you finished)'

while True:

??? adding=input(prompt)

??? if adding == 'quit':

??????? break

??? else:

??????? print(f"我们将在披萨中加入配料{adding}")



#7-5电影票

prompt='请输入你的年龄'

while True:

??? age=input(prompt)

??? age=int(age)

??? if age < 3:

??????? print('你免费')

??????? break

??? elif age >3 and? age < 12:

??????? print('你需要支付十美元')

??????? break

??? elif age > 12:

??????? print('你需要支付十五美元')

??????? break



#7-8 熟食店

sandwich_orders=['tunnayu','niuyouguo','peigen']

finished_sandwiches=[]

while sandwich_orders:

??? finished_sandwich=sandwich_orders.pop()

??? print(f'i made your {finished_sandwich} sandwich')

???

??? finished_sandwiches.append(finished_sandwich)

print("接下来是做好的列表")

for finished_sandwich in finished_sandwiches:

??? print(finished_sandwich.title())

???

???

#7-9 五香烟熏牛肉卖完了

sandwich_orders=['tunnayu','pastrami','niuyouguo','pastrami','peigen','pastrami']

finished_sandwiches=[]

while 'pastrami' in sandwich_orders:

??? sandwich_orders.remove('pastrami')

print(sandwich_orders)

第八章 函数

练习

#8-1消息
def display_message():
        """指出你在本章学的是什么的信息"""
        print("我在本章学的是函数")
display_message()

#8-2喜欢的图书
def favorite_book(title):
    print(f"One of my favorite books is {title}")
favorite_book("Alice in Wonderland")

#8-3T恤
def make_shirt(size,word):
    print(f"这个T恤的尺寸是{size},印在上面的字样是{word}")
print("这种调用方法是位置实参调用：")
make_shirt('m','makabaka')

print("下面这种是关键字实参调用：")
make_shirt(word='yigubigu',size='xs')
    

#8-4大号T恤
"""使用默认值"""
def make_shirt(size,word='i love python'):
    print(f"这个T恤的尺寸是{size},印在上面的字样是{word}")

make_shirt('L')
make_shirt('M')
make_shirt('s','i love c')

#8-5 城市
def describe_city(city_name,city_country='china'):
    print(f"{city_name} in {city_country}")
describe_city('shanghai')
describe_city('kaifeng')
describe_city('london','england')

#8-6城市名
def city_country(city_name,city_country):
    """打印城市的名字和所属国家"""
    print(city_name,city_country)
name_of_city=input("请输入城市名字:")
name_of_country=input("请输入国家的名字：")
city_country(name_of_city,name_of_country)

#8-7专辑
def make_album(singer,name,number=None):
    music={
            'singer':singer,
            'name':name,
            }
    if number:
        music={
                'singer':singer,
                'name':name,
                'number':number,
              }
    return music
music_1=make_album('xusong','yasugongshang')
music_2=make_album('yizhiliulian','haidi')
music_3=make_album('dazhangwei','huluwa','3')
print(music_1)
print(music_2)
print(music_3)

#8-8用户的专辑
def make_album(singer,name,number=None):
    music={
            'singer':singer,
            'name':name,
            }
    if number:
        music={
                'singer':singer,
                'name':name,
                'number':number,
              }
    return music
while True:
    print("\n 接下来请输入你喜欢的歌手相关信息。\n输入q可以退出")
    name_of_music=input('请输入你喜欢的专辑名字：')
    if name_of_music =='q':
        break
    name_of_singer=input('请输入你喜欢的歌手名字：')
    if name_of_singer=='q':
        break
    print(name_of_music,name_of_singer)