>>> import this
The Zen of Python, by Tim Peters

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!

>>> a='python'
>>> a[-1] #从右往左数，-1为开始
'n'
>>> a[-2]
'o'
>>> a[:] #切片
'python'
>>> a[0:]
'python'
>>> a[3:]
'hon'
>>> a[1:2]
'y'

>>> num=0
>>> num-=10
>>> num
-10

>>> 1 in (1,2,3) #'in'相当于集合中的属于符号，其用于判断是否包含在指定的序列中
True
>>> 0 in (1,2,3)
False
>>> (1,2) in (1,2,3) #'in'不想当于集合中的包含符号
False
>>> 1 is 1 #is用于判断两个变量是否为同一个，"=="是判断变量是否相等
<stdin>:1: SyntaxWarning: "is" with a literal. Did you mean "=="?
True
>>> a=1
>>> b=1
>>> a is b 
True
>>> b=2
>>> a is b
False

>>> a=[1,2,3,4,5]
>>> len(a) #元素个数
5
>>> min(a) #最小值
1
>>> max(a) #最大值
5
>>> sum(a) #求和
15
>>> a='123' #也适用于字符串
>>> len(a)
3

>>> a=[1,2,3] 
>>> a.append(4) #添加单个元素
>>> a
[1, 2, 3, 4]
>>> a.extend([5,6]) #添加多个元素，要用列表形式
>>> a
[1, 2, 3, 4, 5, 6]
>>> a.insert(0,0) #在指定位置插入元素，第一个参数为位置，第二个参数为插入内容
>>> a
[0, 1, 2, 3, 4, 5, 6]
>>> a.pop() #删除元素，默认是最后一个元素
6 #返回删除元素的内容
>>> a
[0, 1, 2, 3, 4, 5]
>>> a.pop(0) #删除指定位置的元素
0
>>> a
[1, 2, 3, 4, 5]
>>> a.remove(5) #按元素内容删除元素
>>> a
[1, 2, 3, 4]
>>> del a #直接删除整个变量
>>> a
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'a' is not defined

>>> a=[1,2,3]
>>> a.index(3) #查找指定元素的位置
2
>>> b=[1,1,2,3]
>>> b.index(1) #查找时仅寻找到第一项
0
>>> a.reverse() #反转元素位置
>>> a
[3, 2, 1]
>>> a.count(1) #统计元素出现次数
1
>>> a=[1,1,2,3]
>>> a.count(1)
2
>>> a=[3,1,2,0]
>>> a.sort() #对元素进行排列
>>> a
[0, 1, 2, 3]

>>> a={
... '123':'abc',
... '456':'def'}
>>> a
{'123': 'abc', '456': 'def'}
>>> b=a.copy() #复制a的全部数据
>>> b
{'123': 'abc', '456': 'def'}
>>> b.clear() #清空b的全部数据
>>> b
{}
>>> c=['1.','2.','3.']
>>> c1=dict.fromkeys(c) #从c列表中提取信息以生成一个字典
>>> c1
{'1.': None, '2.': None, '3.': None}
>>> c1=dict.fromkeys(c,'Emtry') #指定字典的默认值
>>> c1
{'1.': 'Emtry', '2.': 'Emtry', '3.': 'Emtry'}
>>> a.get('123') #获取'1,2,3'对应的值
'abc'
>>> a.get('789','Emtry') #若获取对应值失败，返回默认值
'Emtry'
>>> a.keys() #从a字典中提取信息（:前）以生成一个列表
dict_keys(['123', '456'])
>>> '789' in a.keys() #判断某个值是否在字典中
False
>>> a.values() #从a字典中提取信息（：后）以生成一个列表
dict_values(['abc', 'def']) 
>>> a.items()
dict_items([('123', 'abc'), ('456', 'def')]) #从a字典中提取信息（全）以生成一个items
>>> for i in a: #用for遍历时返回:前值
...     print(i)
...
123
456
>>> for i,c in a: #无法一次性遍历全部信息
...     print(i,'->',c)
...
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: too many values to unpack (expected 2)
>>> for i,c in a.items(): #用items方法试试
...     print(i,'->',c)
...
123 -> abc #可以一次性遍历全部信息
456 -> def

>>> a={1,2,3}
>>> a
{1, 2, 3}
>>> b=set({1,2,3,'a','b','c'}) #生成混合集合或空集合时常用set()方法
>>> b.add('d') #添加元素
>>> b
{1, 2, 3, 'a', 'b', 'c'}
>>> b.add(1) #添加元素，但是不会存在多个相同的元素
>>> b
{1, 2, 3, 'a', 'b', 'd', 'c'}
>>> b.remove('d') #删除元素
>>> b
{1, 2, 3, 'a', 'b', 'c'}
>>> a={1,2,3}
#常见集合运算
>>> print('交集',a&b)
交集 {1, 2, 3}
>>> print('并集',a|b)
并集 {1, 2, 3, 'a', 'b', 'c'}
>>> print('差集',a-b)
差集 set()
>>> print('差集',b-a)
差集 {'a', 'b', 'c'}
>>> print('对称差集',b^a)
对称差集 {'a', 'b', 'c'}>>> b.add(1)

>>> a=[a for a in range(3)]
>>> a
[0, 1, 2]
>>> c=[b for b in range(5) if b!=2] #添加一个条件
>>> c
[0, 1, 3, 4]

>>> def main(a,b=123):
...     print('a=',a)
...     print('b=',b)
...
>>> main(123)
a= 123
b= 123
>>> main(456,000)
a= 456
b= 0

>>> def main(abc,*args,**kwargs):
...     print('abc=',abc)
...     print('args=',args)
...     print('kwargs=',kwargs)
...
>>> main(abc=123,name='Whitemu')
abc= 123
args= ()
kwargs= {'name': 'Whitemu'}
>>> def main(*args):
...     print(args)
...
>>> main(456)
(456,)
>>> main(456,789)
(456, 789)

>>> def main():
...     '''
...     It is a main
...     '''
...     print('main')
...
>>> main.__doc__
'\n\tIt is a main\n\t'
>>> help(main)
Help on function main in module __main__:

main()
    It is a main

def main(time:str='Input your time',Mode:str="Y or N?") -> str:
    '''
    main函数帮助文档：
    time - 你的时间，字符串
    Mode - 模式，仅支持Y或N
    '''
    print('The time is',time)

class Stu:
    def __init__(self,name):
        self.name=name
        self.__name='WhitemuTeam' #定义私有属性:__name，类似的，还有__abc之类，只需要在前面加上__即可
    def main(self):
        print('Your name is:',self.name)
        print('My name is',self.__name)

stu=Stu('White_mu')
stu.main()
print('The name in Stu is',stu.name)
print('The __name in Stu is',stu.__name)

Your name is: White_mu
My name is WhitemuTeam
The name in Stu is White_mu
Traceback (most recent call last):
  File "C:\Users\28734\Desktop\main.py", line 12, in <module>
    print('The __name in Stu is',stu.__name)
AttributeError: 'Stu' object has no attribute '__name'

#a=1
try:
    print(a)
except:
    print('Error')
finally: #无论是否有异常都会执行下列语句
    print('exit...')

try:
    print(a)
except KeyboardInterrupt:
    print('Error')
finally:
    print('exit...')

C:\Users\28734\Desktop>py main.py
exit... #可以看到即使报错也可以执行finally子句下的内容
Traceback (most recent call last):
  File "C:\Users\28734\Desktop\main.py", line 2, in <module>
    print(a)
NameError: name 'a' is not defined

import sys

a=sys.argv
print(a)

import os

print("__file__:",__file__)
print("os.path.dirname(__file__):",os.path.dirname(__file__))

import os

print(os.getcwd()) #获取当前路径，输出：C:\Users\28734\Desktop（即源cmd当前路径，否则就是文件路径）
os.chdir("c:\\") #切换路径
print(os.getcwd())

import os

os.rename("a.text", "b.txt")

import os

folder = os.path.exists("c:\windows") #查看指定的路径是否存在
print(folder) #若存在，返回True，若不存在，则False

import os

folder = os.path.isfile("c:\\windows\\system32")
print(folder) #若是一个文件，则True，若不是或不存在，则False

import os

folder = os.path.isdir("c:\\windows\\system32")
print(folder) #若是一个文件夹，则True，若不是或不存在，则False

import os

os.mkdir("d:\\mu")

import os

os.makedirs("d:\\mu1\\mu2\\mu3")

import random

print(random.random()) #用于生成随机0~1的浮点数，不能指定参数
print(random.randint(1,100)) #用于生成随机整数
print(random.uniform(1,100)) #用于生成随机浮点数

import random

seq1 = (1, 15, 8, 97, 22)
seq2 = ["星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六"]
print(random.choice(seq1)) #用于随机抽取序列中的元素
print(random.choice(seq2))

>>> f=open('abc.txt','r')
>>> f.readline()
'123\n'
>>> f.readline()
'abc\n'
>>> f.readline()
'efg'

>>> f=open('abc.txt','r')
>>> a=f.readlines()
>>> a
['123\n', 'abc\n', 'efg']

>>> open('abc.txt','w')
>>> f.writelines(['hello','world'])

>>> import time
>>> print('当前时间:',time.localtime())
当前时间: time.struct_time(tm_year=2021, tm_mon=10, tm_mday=1, tm_hour=8, tm_min=3, tm_sec=30, tm_wday=4, tm_yday=274, tm_isdst=0)
>>> print('当前时间:',time.asctime(time.localtime()))
当前时间: Fri Oct  1 08:04:41 2021

>>> import datetime
>>> print('当前日期',datetime.date.today())
当前日期 2021-10-01
>>> print('当前是星期几',datetime.date.today().weekday())
当前是星期几 4

import time

times=time.time()

for i in range(10):
	time.sleep(1)

print('代码运行时间',time.time() -times)

>>> import hashlib
>>> text='Hello world'
>>> hashlib.md5(text.encode()).hexdigest()
'3e25960a79dbc69b674cd4ec67a72c62'

>>> import base64
>>> text='Hello world'
>>> base64text=base64.b64encode(text.encode())
>>> print('base64加密后：',base64text)
base64加密后： b'SGVsbG8gd29ybGQ='
>>> newtext=base64.b64decode(base64text)
>>> print('base64解密后',newtext)
base64解密后 b'Hello world'

import os
cmd=os.getcwd()

import os
py=os.path.dirname(os.path.abspath(__file__))

import os
file='E:\...\xxx.jpg' #文件目录
#获取文件名
filedir=os.path.split(file) #filedir: ['E:\...\xxx.jpg','xxx.jpg']
filename=filedir[1] #filename: xxx.jpg
#拆分文件名
file=filename.split('.') #以“.”号分割字符串 file: ['xxx','jpg']
name=file[0] #name: xxx
houzui=file[1] #houzui: jpg

a='123456.6543321.000000'
a1=a.split('.') #a1: 123456

import datetime
time = datetime.datetime.now() #获取当前时间（2021-08-15 23:50:40.236077）
realtime = time.strftime("%Y-%m-%d") #格式化获取到的时间（2021-08-15）

from dateutil import parser
d1 = '2021-01-01'
d2 = '2021-02-01'
days = str((parser.parse(d2) - parser.parse(d1)).days)

from xml.dom import minidom
dom=minidom.parse("temp.xml") #加载和读取XML文件
root=dom.documentElement #获取XML文档对象
msg = root.getElementsByTagName('copyright') #数据所在节点名
information1 = msg[0].firstChild.data #获取文本名
print('拍摄地(作者)：',information1)

from threading import Thread  
t1 = Thread(target=first) #指定t1线程的任务——运行first函数
t2 = Thread(target=sec) #指定t2线程的任务——运行sec函数
#多线程开始
t1.start()
t2.start()

import cv2
from PIL import ImageFont, ImageDraw, Image
import numpy as np	
bk_img= cv2.imread("first.jpg") #读取first.jpg
word = 'Hello world' #此处写你的句子
fontpath= "HarmonyOS_Sans_SC_Black.ttf" #设置字体
font= ImageFont.truetype(fontpath,32) #设置字体长度
img_pil= Image.fromarray(bk_img) #转换数据
draw= ImageDraw.Draw(img_pil) #简化模块长度
draw.text((70,230), word, font= font, fill= (0,0,0))
#绘制文字信息，(70,230)为字体的位置，(0,0,0)为颜色RGB码
bk_img= np.array(img_pil) #转换数组
cv2.imshow("finally",bk_img) #展示图片
cv2.waitKey() #展示图片时按任意键继续
cv2.imwrite("finally.jpg",bk_img)#写入图片

import webbrowser
url = 'https://muspace.top'
webbrowser.open_new(url)

import win32api
import win32con
key = win32api.RegOpenKey(win32con.HKEY_LOCAL_MACHINE,'SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters',0, win32con.KEY_ALL_ACCESS)
#定位：key = win32api.RegOpenKey(win32.com.[第一级目录],'注册表位置',0,win32con.KEY_ALL_ACCESS)
win32api.RegCreateKey(key,'{2227A280-3AEA-1069-A2DE-08002B30309D}')
#新建项：win32api.RegCreateKey(key,'[项名]')
win32api.RegSetValueEx(key,'EnablePrefetcher',0,win32con.REG_SZ,'00000001')
#写注册表：win32api.RegSetValueEx(key,'[值名]',0,win32con.[值类型],('[值]'))

def txt():
    import random
    with open('sen.txt', 'r' , encoding='utf8') as f: #打开sen.txt
        datas = f.readlines() #按换行符获取值
        data  =  random.choice(datas) #随机选择数据
    if data.strip() == '': #当获取到的数据为空时
        txt() #重新执行函数
    else:
        return data.strip() #反之，返回值

import numpy as np
from PIL import Image
from pyzbar import pyzbar
import glob
import os
import sys

PATH_TO_TEST_IMAGES_DIR = os.path.dirname(os.path.abspath(__file__)) #获取Py文件所在路径
img=PATH_TO_TEST_IMAGES_DIR + "/*.[jp][pn]g"

for pidImage in glob.glob(img): #查找jpg和png文件
    print('要解析二维码的图片: ',pidImage)
    im = np.array(Image.open(pidImage)) # 读取文件，转成数组
try:
    print(pyzbar.decode(im)[0].data.decode("utf-8")) # 输出内容
    os.remove(pidImage) #扫过移除二维码
    print('识别完毕，自动移除二维码')
except:
    print('无法识别二维码,请检查你的图片是否正确或确认程序根目录中含有图片')

from PIL import Image 
pidImage='xxx.jpg'
im = Image.open(pidImage).convert('RGB') # 打开图片
im.save(newfilename,'webp') #以webp方式保存图片

# switch = {"valueA":functionA,"valueB":functionB,"valueC":functionC}
# try:
#　　switch["value"]() #执行相应的方法。
# except KeyError as e:
#       pass 或 functionX #执行default部分

switch = {
    "a":lambda:x:x*2,
    "b":lambda:x:x*3,
    "c":lambda:x:x**x
}
try:
    swtich["c"](6)
except KeyError as e:
    pass

from tqdm import tqdm
for i in tqdm(range(100000)):
	#print('hello world')

import zipfile
with zipfile.ZipFile(zipname) as zf:
                zf.extractall()

for file in os.listdir(imgdir):
	newname=file+'.jpg'
	new_name=file.replace(file,newname)
	#重命名
    os.renames(os.path.join(imgdir,file),os.path.join(imgdir,new_name))

if ctypes.windll.shell32.IsUserAnAdmin():
	# main()
else:
    ctypes.windll.shell32.ShellExecuteW(None, "runas", sys.executable, __file__, None, 1)