www.python.org

Add Python 3.11 to PATH

1.打开cmd 

2.输入python,出现对应的版本

#整型转换为字符串类型
a = 12 
str(a)

#输出一些特殊符号
a = ('a\'b')
a

print('a\nb')

a = "Sheldon"
b = " is perfect"
a+""+b

name = 'Sharon'
#按编号提取任意字符
name[0] #取第一个字母
name[-1] #取最后一个字母

#name[start:end] 前包括后不包括
name[0:2] 

#name[start:end:step]
name[::2] 

name[::-1] #取反

name = "sheldon"
len(name)

web = "www.baidu.com"
web.split('.')

web ='www.baidu.com'
web.count('.')

head = '-'
web = 'www.baidu.com'
head.join(web)

info = ['name','age','sex','1.0','True','(1,2)','[3,4]']
info

#字符串转列表
name = 'Sheldon'
list(name)

#tuple转列表
number = (3,4,5)
list(number)

#字典转数组
info = {'name':'sheldon','age':'32'}
list(info)

name_list = ['sheldon','sharon','anna']
#a[index]
name_list[0]
#a[start:end]
name_list[:2]
#a[start:end:step]
name_list[1:2:1]

name_list = ['sheldon','sharon','anna']
#依据元素位置修改元素
name_list[0] = 'davad'
name_list

#添加到元素尾部 list.append('element')
name_list.append('lily')
name_list

#指定位置插入指定的值 list.insert(position,element)
name_list.insert(0,'sheldon')
name_list

#list.pop()删除最后一个元素,返回值：删除后的元素
name_list.pop()

# del list[position],删除指定位置的元素
del name_list[0]

# list.remove('移除列表中的元素')
name_list.remove('anna')

#del name_list 删除整个列表
del name_lis

lis = [[1,2],[3,4]]
lis[0][1]

list1 = ['name']
list2= ['age']
list1 + list2

#在list1的基础上添加上list2,在尾部添加
list1.extend(list2)
list1

# 使用in判断一个元素是否在list中
# 语法：element in list
#返回值 True / False
'age' in list1

#查看一个列表的长度;返回值 列表的长度，
len(name_list)

num = [1,2,3,2,4]
num.index(2)

#1直接创建 dic = {key:value}
dic = {'name':'sheldon'}
dic

#2dict()方法创建
dict(name='sheldon',age = 30)

#3 zip()方法创建
dict(zip(['name','sex','age'],['sheldon','male','30']))

#dic[key]，返回值对应的value
dic['name']

# dic.get()
# 语法：dic.get(key,value) 返回值value,不存在返回None
dic.get('name')

# 判断某个值是否在字典中 key in dic 
'name' in dic

dic['sex'] = 'male'
dic

dic['sex'] = 'female'
dic

#update()字典的合并
D = {'one': 1, 'two': 2}
D.update({'three': 3, 'four': 4})  # 传一个字典
D

del dic['sex']
dic

# dict.keys()函数以列表返回一个字典所有的keys
dic.keys()

# dict.values()函数以列表返回一个字典所有的values
dic.values()

# dict.items()函数以列表返回一个字典所有的(key,value)元组数组。
dic.items()

tup = (1,2,3)
tup

tup[0]

#Python 元组 tuple() 函数将列表转换为元组。
#语法：tuple( iterable )
lis = ['sheldon','sharon']
tuple(lis)

#直接创建
{'sharon',5}

#set()函数创建
lis = ['sheldon','sharon']
set(lis)

set1 = {1,2,3,'a','b'}
set2 = {2,3,'b','c'}
# 交集 &
set1 & set2
# 并集 |
set1 | set2
# 差集 -
set1 - set2

1>2 
1<2<3
42 != '42'
'Name' == 'name'
'M' in 'Magic'
number = 12
number is 12

==  #左右两边等值得时候返回 True
!= #左右两边不相等时返回 True
> #左边大于右边得时候返回 True
< #左边小于或等于右边得时候返回True
<= #左边小于或等于右边得时候返回True
>= #左边大于或等于右边得时候返回True

# 多条件比较
middle = 5 
1< middle < 10 

#变量得比较
two = 1+1 
three = 1+3 
two < three

album = ['Black Star','David Bowie',25,True]
25 in album

and 、 or用于布尔值之间的运算 

not x # 如果x是True,则返回False,否则返回True.
x and y #and表示”并且“，如果x和y都是True,则返回True,x和y有一个false ，则返回false.
x or y #or表示或者，如果x或y有其中一个是True,则为True,如果x和y都是false，则返回false.

# creat  a list
password_list = ['##','12345']

# input a password
password=input('password:')

password_correct = (password ==password_list[-1])
password_reset = (password ==password_list[0])
# if-else

if password_correct:
    print('Login Success!')

elif password_reset:
    new_password = input('Enter a new password:')
    password_list.append(new_password)
    print('Your password has changed successfully!')

else:
    print('Wrong password or invalid input!')

for i in range(1,10):
    for j in range(1,i+1):
        print('{}X{}={}'.format(i,j,i*j),end=' ')
    print('\n')

#是2的倍数变平方，输入666 退出
while True:
    num = int(input('Please enter a num:'))
    if num == 666:
        break
    if num%2!=0:
        continue
    print(num**2)

#普通的列表添加元素
a = []
for i in range(1,11):
a.append(i)

# 列表推导式添加元素
b = [i for i in range(1,11)]

#自带函数
print()
input()

#先定义
def converter(C):
    fa= C * 9/5 +32
    print(str(fa)+'F')

#再使用
print(converter(35))
#返回值

def trapezoid_area(base_up, base_down, height):
    return 1/2 * (base_up + base_down) * height

trapezoid_area(1,2,3)
# 填入的参数1，2，3分别对应着参数base_up,base_down,和hight，这种传入参数的方式为位置参数。

# 一个 lambda 函数，它把作为参数传入的数字加 10，然后打印结果：
x = lambda a: a+10 
x(5)
# 注意：x是函数名

def text_create(name,msg):
        path = 'D:\\AI\\05python\\'
        full_path = path +name+'.txt'
        file = open(full_path,'w')
        file.write(msg)
        file.close()
        print(full_path)
        
text_create('hello','hello world')

def text_filter(word,censored_word='lame',changed_word='Awesome'):
        return word.replace(censored_word,changed_word)
t=text_filter('Python is lame')
print(t)

def text_censored_create(name,msg):
        clean_msg=text_filter(msg)
        text_create(name,clean_msg)
tt=text_censored_create('Try','lame!lame!lame!')
print(tt)

try:
    # 执行要尝试 (try) 的代码
except：
    # 执行应对异常发生时的代码
    
#Python 从 try 子句开始执行，若一切正常，则跳过 except 子句；若发生异常，则跳出 try 子句，执行 except 子句。

try:
    file = open('test.py')  # 不存在的文件
    print('Everything went well!')  # 打印顺利运行提示信息
except:
    print('Something went wrong!')  # 处理异常方式：打印错误提示信息

try:
    file = open('test.py')  # 不存在的文件
    print('Everything went well!')  # 打印顺利运行提示信息
except Exception as e:   #把Exception 错误保存在变量e中
    print('Something went wrong!',e)  # 处理异常方式：打印错误提示信息

try:
    file = open('test.py')
    print('Everything goes well!')
except FileExistsError as e:  # 捕获特定类型异常
    print('There is a FileExistsError!',e)
except FileNotFoundError as e:  # 捕获特定类型异常
    print('There is a FileNotFoundError!',e)

t

v = 1/0

int int

List = [2]
List[3]

Dic = {'1':'yes', '2':'no'}
Dic['3']

f = open('abc')

class Worker:
 def Work():
    print("I am working")

w = Worker()
w.a

int('d')

iStr = '22'
iVal = 22
obj = iStr + iVal

assert 1 != 1

v = 1/0

#导入
import 模块名称
#使用
模块名称.函数名()

#导入
import 模块名称 as 别名
#使用
别名.函数名()

#导入
from 模块名称 import 函数名称
#使用
函数名()

#导入
from 模块名称 import 函数名称 as 别名
#使用
别名()

python自带的库

https://docs.python.org/zh-cn/3/library/index.html

包 管理工具 

https://pypi.org/

pip install 包名

pip install numpy==1.13.1

注：版本范围符号：==、>=、<=、>、<。

pip uninstall 包名

pip install --upgrade pip

pip install -r requirement.txt

#可口可乐
class CocaCola:
    formula = ['caffeine','sugar','water','soda']
#formula 类的属性（Class Attribute）

#instance
coke_for_me = CocaCola()
coke_for_you = CocaCola()

print(CocaCola.formula)
print(coke_for_me.formula)
print(coke_for_you.formula)

for element in coke_for_me.formula:
    print(element)

#instance
coke_for_China = CocaCola()

#instance attribute
coke_for_China.local_logo = '可口可乐'
print(coke_for_China.formula)
print(coke_for_China.local_logo)

#可口可乐
class CocaCola:
    #formula 类的属性（Class Attribute）
    formula = ['caffeine','sugar','water','soda']
    #实例方法  self是实例对象   self可以随意修改名称
    def drink(self):
        print('Energy!')

#使用实例方法
coke = CocaCola() #1 实例化
coke.drink() #2引用类的方法

#证明：
coke.drink() 
#相当于 
CocaCola.drink(coke)

class CocaCola:
    formula = ['caffeine','sugar','water','soda']
    def drink(self,how_much):
        if how_much =='a sip':
            print('Cool!')
        elif how_much == 'whole bottle':
            print('Headache!')

ice_coke = CocaCola()
ice_coke.drink('a sip')

class CocaCola:
    formula = ['caffeine','sugar','water','soda']
    def __init__(self):
        self.local_logo = '可口可乐'
    
    def drink(self):
        print('Energy!')

coke = CocaCola()
coke.drink()
coke.local_logo

class CocaCola:
    formula = ['caffeine','sugar','water','soda']
    def __init__(self,local_name):
        self.local_logo = local_name
    
    def drink(self):
        print('Energy!')

coke=CocaCola('可口可乐')
coke.local_logo

coke.drink()

class CocaCola:
    calories = 140
    sodium = 45
    total_carb = 39
    caffeine = 34
    ingredients = ['High Fructose Corn Syrup', 'Carbonated Water','Phosphoric Acid','Natural Flavors','Caramel Color','Caffeine']
    def __init__(self,logo_name):
        self.local_logo = logo_name
    def drink(self):
        print('You got {} cal energy!'.format(self.calories))

coca=CocaCola("可口可乐")
coca.drink()
coca.local_logo

class CaffeineFree(CocaCola):
    caffeine = 0
    ingredients = ['High Fructose Corn Syrup','Carbonated Water','Phosphoric Acid','Natural Flavors','Caramel Color']

coca_a = CaffeineFree('CocaCola-free')
coca_a.drink()
coca_a.local_logo

class Animial:
    #属性
    def __init__(self,weight,hight):
        self.weight = weight
        self.hight = hight
    #方法
    def shout(self):
        print('woo~')

dog = Animial(30,100)
print(dog.weight)
dog.hight

class Dog(Animial):
    pass

dog_1 = Dog(20,40)
dog_1.shout()

class Cat(Animial):
    #add method
    def run(self):
        print('running...')
    #repire method
    def shout(self):
        print('miaomiao~')

cat = Cat(15,30)
cat.run()
cat.shout()

class Pig(Animial):
    def  __init__(self,weight,hight,color):
        super().__init__(weight,hight)
        self.color = color

pig = Pig(20,300,'write')

pig.color

class TestA:
    attr = 1
#实例的属性
obj_a = TestA()
print(obj_a.attr)
#重新赋值类的属性
TestA.attr = 42
print(obj_a.attr)

class TestA:
    attr = 1
    
obj_a = TestA()
obj_b = TestA()
obj_a.attr = 42
print(obj_a.attr)
print(obj_b.attr)

class TestA:
    attr = 1 #类的属性
    def __init__(self): #实例的属性
        self.attr = 42
        
obj_a = TestA()
print(obj_a.attr)

class Dog():
    count = 0
    def __init__(self,weight):
        Dog.count+=1
        self.weight = weight
    @classmethod
    def dog_num(cls):#类的方法
        print('we have {} dogs'.format(cls.count))
        
dog1 = Dog(10)
dog2 = Dog(12)
dog3 = Dog(14)
Dog.dog_num()

不创建类实例的情况下调用方法。

import datetime
class Time:
    def __init__(self,time):
        self.time=time
    @staticmethod
    def get_time():
        return datetime.datetime.now()

Time.get_time()

class Dog:
    def __init__(self,name):
        self.name = name
    def __str__(self):
        print("Class Dog:")
        return self.name
dog=Dog("keji")
print(dog)

class Dog:
    def __init__(self,name):
        self.name = name
    def __repr__(self):
        print("Class Dog:")
        return self.name
dog=Dog("keji")
dog

class MyAdd:
    def __init__(self,num):
        self.num = num
    def __add__(self,other):
        return self.num+other.num
    
a=MyAdd(10)
b = MyAdd(7)
a+b

fn_path = 'D:/AI/05python/类/first_name.txt'
ln_path = 'D:/AI/05python/类/last_name.txt'

fn=[]
ln1=[] #单字名
ln2=[] #双字名

#读取姓氏
with open(fn_path,'r',encoding='utf-8') as f:
    #每次一行
    for line in f.readlines():
        fn.append(line.split('\n')[0])
fn=tuple(fn)
print(fn)

#读取名
with open(ln_path,'r',encoding='utf-8') as f:
    #每次一行
    for line in f.readlines():
        last_name= line.split('\n')[0]
        if len(last_name)==1:
            ln1.append(last_name)
        elif len(last_name)==2:
            ln2.append(last_name)
ln1 =tuple(ln1)
ln2 = tuple(ln2)
print(ln1,ln2)

import random
class FakeUser:
    def __init__(self,num):
        self.num=num
    def fake_name(self):
            if self.num==1:
                full_name = random.choice(fn)+random.choice(ln1)
            else:
                full_name = random.choice(fn)+random.choice(ln2)
            return full_name
    
    def fake_gender(self):
        gender = random.choice(['male','female'])
        return gender

#num=input('请输入名几个字：')
user_a = FakeUser(2)
user_a.fake_name(),user_a.fake_gender()

#子类
class SnsUser(FakeUser):
    def __init__(self,count):
        self.count = count
    def get_followers(self):
        for i in range(self.count):
            followers = random.randrange(1,10)  
            print(followers) 

user_b = SnsUser(FakeUser)
user_b.get_followers()

poem = 'you are my sunshine!!!'

f = open('sunshine.txt','wt') 
f.write(poem)
f.close()

f = open('sunshine.txt','rt')
p = f.read()
f.close()

p

b_p = p.encode()
b_p 

f = open('b_sunshine','wb')
f.write(b_p)
f.close()

f=open('b_sunshine','rb')
bp=f.read()
f.close()

bp

编码：字符串使用unicode编码，为每一个字符编码成二进制格式。
str = '中文'
解码：二进制解码成文本

#编码 
s = '一起学AI'
b_s=s.encode()
b_s

#解码
b_s.decode()

#写
with open('sunshine2.txt','w') as file:
    file.write(poem)

#追加
with open('sunshine2.txt','a') as file:
    file.write(poem)

#读
with open('sunshine2.txt','r') as file:
    p=file.read()

p

with open('Saying Good-bye to Cambridge Again.txt','rt',encoding='utf-8') as file:
    p=file.read()

print(p)

with open('Saying Good-bye to Cambridge Again.txt','rt',encoding='utf-8') as file:
        p=file.readline()

p

poem=''
with open('Saying Good-bye to Cambridge Again.txt','rt',encoding='utf-8') as file:
        while True:
            line=file.readline()
            if not line:
                break
            else:
                poem+=line
print(poem)

with open('Saying Good-bye to Cambridge Again.txt','r',encoding='utf-8') as file:
    lines = file.readlines()

print(lines)

f = open('Saying Good-bye to Cambridge Again.txt','r',encoding='utf-8')
for line in f: 
    line=line.upper()
    print(line)
f.close()

students = "'Anna','Sheldon','Sharon'"
with open('students.txt','w') as file:
    file.write(students)

import csv 
students = ['Anna','Sheldon','Sharon']
with open('students.csv','w') as file:
    csv_file=csv.writer(file) 
    csv_file.writerow(students)

#追加
with open('students.csv','a') as file:
    csv_file=csv.writer(file)
    csv_file.writerow(['Sun'])

student = [['Anna'],['Sheldon'],['Sharon']]

with open('student.csv','w',newline='') as file:
    csv_file = csv.writer(file)
    csv_file.writerows(student)

student4 = [['sun']]
with open('student.csv','a',newline='') as file:
    csv_a=csv.writer(file)
    csv_a.writerows(student4)

with open('student.csv','r') as file:
    csv_file=csv.reader(file)
    student=[i for i in csv_file]

print(student)

import pandas as pd 
database=pd.read_excel('test01.xlsx')

data=database.to_csv('test01.csv',encoding='utf-8')

pd.read_csv('test01.csv')

data = {'name':'一起学AI','wechat':'zhaixueziyue','备注':'学AI'}

data

import json
learningAI=json.dumps(data,ensure_ascii=False)
learningAI

json.loads(learningAI)

import datetime
time = datetime.datetime.now()
print(time)

import pickle
pickle_time=pickle.dumps(time)
pickle_time

time=pickle.loads(pickle_time)
print(time)

list =['Sheldon','Sharon','Sun']

name=pickle.dumps(list)
name

pickle.loads(name)