python操作excel
计算项目代码总量
批量更改名字
读取.txt文件
单词的总量
单词出现的频率
统计字母在字符串中出现的次数
asyncio
协程
UDP
TCP
socket请求新浪主页
GUI编程
chardet
pillow图片操作库
生成字母验证码图片
psutil 运维
urllib
contextlib
hmac
hashlib
base64
struct
collections
datetime
正则表达式
多线程
os
json
pickle
文件
functools
枚举
杨辉三角形

python操作excel

写入excel

import json
import xlrd #读取数据
import xlwt #写入数据
import xlutils #操作excel

dir = '/Users/ly/Desktop/Python/py-test/txt-test/student.txt'
excel_file = r'/Users/ly/Desktop/Python/py-test/txt-test/stu.xls'
s = ''
with open(dir, 'r') as f:
    s = f.read()
    f.close()
jsons = json.loads(s)
row = len(jsons)
clos = []
for j in jsons:
    clos.append(len(jsons[j]))
clo = max(clos)
#对excel的写操作
# 创建一个Workbook对象，这就相当于创建了一个Excel文件
'''
Workbook类初始化时有encoding和style_compression参数
encoding:设置字符编码，一般要这样设置：w = Workbook(encoding='utf-8')，就可以在excel中输出中文了。
默认是ascii。当然要记得在文件头部添加：
#!/usr/bin/env python
# -*- coding: utf-8 -*-
style_compression:表示是否压缩，不常用。
'''
book = xlwt.Workbook(encoding='utf-8', style_compression=0)
#创建一个sheet对象，一个sheet对象对应Excel文件中的一张表格。
'''
其中的test是这张表的名字,cell_overwrite_ok，表示是否可以覆盖单元格，其实是Worksheet实例化的一个参数，默认值是False
'''
sheet = book.add_sheet('student', cell_overwrite_ok=True)
# 向表test中添加数据
#1.表头
titles = ['序号','姓名','数学','物理','化学']
for i in range(clo + 1):
    sheet.write(0,i,titles[i])
index = 1
for j in jsons:
    sheet.write(index,0,j)
    jj = jsons[j]
    for i in range(row):
        sheet.write(index,i+1,jj[i])
    index += 1
book.save(excel_file)

读取excel

book = xlrd.open_workbook(excel_file)#得到Excel文件的book对象，实例化对象
sheet1 = book.sheet_by_index(0)# 通过sheet索引获得sheet对象
print(sheet1)#<xlrd.sheet.Sheet object at 0x1048a0550>
sheet_name = book.sheet_names()[0]# 获得指定索引的sheet表名字
print(sheet_name)
# 通过sheet名字来获取，当然如果知道sheet名字就可以直接指定
sheet2 = book.sheet_by_name(sheet_name)
rows = sheet2.nrows# 获取行总数
print(rows)
# 获得第1行的数据列表
print(sheet2.row_values(0))
# 获得第1列的数据列表
print(sheet2.col_values(0))
# 通过坐标读取表格中的数据
cols = sheet2.ncols
for x in range(rows):
    for y in range(cols):
        print(sheet2.cell_value(x,y))

计算项目代码总量

dir = '/Users/ly/Desktop/qixiaofu/qixiaofu'
#列出所有文件路径，递归
def get_all_dirs(dir):
    list1 = []
    def all_dirs(dir):
        for d in os.listdir(dir):
            file = os.path.join(dir,d)
            if '.' in d:
                if d[d.rfind('.')+1:].lower() in ['swift']:
                    list1.append(file)
            else:
                if os.path.isdir(file):
                    all_dirs(file)
    all_dirs(dir)
    return list1
l = get_all_dirs(dir)
line_num = 0
for s in l:
    with open(s,'r') as f:
        line_num += len(f.readlines())
print(line_num)#37357

批量更改名字

#方法一
import os
from datetime import datetime
def changeName(filePath, name):
    files = os.listdir(filePath)
    for i in range(len(files)):
        file = os.path.join(filePath,files[i])  
        if '.' in files[i]:
            pos = files[i].rindex('.')
            suffix = files[i][pos:]
            if suffix.lower() in ['.png', '.jpeg', '.jpg']:
                new = os.path.join(filePath,name+str(i)+suffix.lower())
                os.rename(file,new)
filePath = '/Users/ly/Desktop/Python/picture/20180116'
changeName(filePath,'jianshu')

#方法二
import os
from datetime import datetime
def changeName(filePath, name):
    now = datetime.now()
    newPath = os.path.join(filePath, now.strftime('%Y%m%d'))
    if os.path.exists(newPath):
        for fi in os.listdir(newPath):
            os.remove(os.path.join(newPath,fi))
        os.rmdir(newPath)
    os.mkdir(newPath)
    files = os.listdir(filePath)
    for i in range(len(files)):
        file = os.path.join(filePath,files[i])  
        if '.' in files[i]:
            pos = files[i].rindex('.')
            suffix = files[i][pos:]
            if suffix.lower() in ['.png', '.jpeg', '.jpg']:
                with open(file, 'rb') as f1:
                    new = os.path.join(newPath,name+str(i)+suffix.lower())
                    with open(new,'ab') as f2:
                        f2.write(f1.read())
                        f2.close()
                        print(i)
filePath = '/Users/ly/Desktop/Python/picture'
changeName(filePath,'jianshu')

任一个英文的纯文本文件，统计其中的单词出现的个数。

读取.txt文件

def read_txt(dir):
    with open(dir,'r') as f:
        return f.readlines()
    return ''

单词的总量

dir = '/Users/ly/Desktop/test.txt'
line_num = 0
for line in read_txt(dir):
    words = str(line).split(' ')
    line_num += len(words)
print(line_num)

单词出现的频率

d = dict()
for line in read_txt(dir):
    words = str(line).split(' ')
    for word in words:
        if str(word) in d:
            d[str(word)] += 1
        else:
            d[str(word)] = 1
print(d)

统计字母在字符串中出现的次数

set = set()
test_string = 'eratyuiaopdaafaahjakaalxcvabnmeraatyuiaaofghjkcvbnamdfaghjaratyufaghjk'
for s in test_string:
    set.add(s)
set = set(test_string)
for c in set:
    print(test_string.count(c))

import time
print('begin--', time.time())
ss = ''
for i in range(1000000):
    ss += test_string
print('start for--', time.time())
s1 = time.time()
set1 = set()
for s in ss:
    set1.add(s)
print('end for--', time.time())
e1 = time.time()
print('start set--', time.time())
s2 = time.time()
set2 = set(ss)
print('end set--', time.time())
e2 = time.time()
print(e1 - s1)#9.377879858016968
print(e2 - s2)#1.0037169456481934

'''
使用‘set2 = set(ss)’的效率是使用‘for s in ss: set1.add(s)’效率的9倍左右，
所以千万别随意使用for循环
'''

asyncio

import asyncio
@asyncio.coroutine
def wget(host):
    print('wget %s...' % host)
    connect = asyncio.open_connection(host, 80)
    reader, writer = yield from connect
    header = 'GET / HTTP/1.0\r\nHost: %s\r\n\r\n' % host
    writer.write(header.encode('utf-8'))
    yield from writer.drain()
    while True:
        line = yield from reader.readline()
        if line == b'\r\n':
            break
        print('%s header > %s' % (host, line.decode('utf-8').rstrip()))
    # Ignore the body, close the socket
    writer.close()
loop = asyncio.get_event_loop()
tasks = [wget(host) for host in ['www.sina.com.cn', 'www.sohu.com', 'www.163.com']]
loop.run_until_complete(asyncio.wait(tasks))
loop.close()

把@asyncio.coroutine替换为async；把yield from替换为await。

async def wget(host):
    print('wget %s...' % host)
    connect = asyncio.open_connection(host, 80)
    reader, writer = await connect
    header = 'GET / HTTP/1.0\r\nHost: %s\r\n\r\n' % host
    writer.write(header.encode('utf-8'))
    await writer.drain()
    while True:
        line = await reader.readline()
        if line == b'\r\n':
            break
        print('%s header > %s' % (host, line.decode('utf-8').rstrip()))
    writer.close()
loop = asyncio.get_event_loop()
tasks = [wget(host) for host in ['www.sina.com.cn', 'www.sohu.com', 'www.163.com']]
loop.run_until_complete(asyncio.wait(tasks))
loop.close()

协程

def consumer():
    r = ''
    while True:
        n = yield r
        if not n :
            return
        print('Consumer %s...' % n)
        r = '200 OK'
def produce(c):
    c.send(None)
    n = 0
    while n < 5:
        n += 1
        print('Producing %s...' % n)
        r = c.send(n)
        print('Consumer return %s...' % r)
    c.close()
c = consumer()
produce(c)
# consumer函数是一个generator，把一个consumer传入produce后：
# 首先调用c.send(None)启动生成器；
# 然后，一旦生产了东西，通过c.send(n)切换到consumer执行；
# consumer通过yield拿到消息，处理，又通过yield把结果传回；
# produce拿到consumer处理的结果，继续生产下一条消息；
# produce决定不生产了，通过c.close()关闭consumer，整个过程结束。
# 整个流程无锁，由一个线程执行，produce和consumer协作完成任务，所以称为“协程”，而非线程的抢占式多任务

UDP

import socket
# ####服务端######
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
#绑定端口
s.bind(('127.0.0.1', 9999))
print('bind UDP on 9999...')
while True:
    #接收数据
    data, addr = s.recvfrom(1024)
    print('received from %s:%s' % addr)
    s.sendto(b'hello, %s' % data, addr)
####客户端######
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
for data in [b'Michael', b'Tracy', b'Sarah', b'ly', b'wj', b'lw', b'hah']:
    #发送数据
    s.sendto(data, ('127.0.0.1', 9999))
    #接收数据
    print(s.recv(1024).decode('utf-8'))
s.close()

TCP

# 导入socket库:
import socket, time, threading
####服务端######
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(('127.0.0.1', 9999))#监听端口
s.listen(5)
print('Watting for connection ...')

def tcplink(sock, addr):
    print('Aaccept new connection from %s:%s' % (addr))
    sock.send(b'Welcom!')
    while True:
        data = sock.recv(1024)
        time.sleep(1)
        if not data or data.decode('utf-8') == 'exit':
            break
        sock.send(('hello, %s' % data.decode('utf-8')).encode('utf-8'))
    sock.close()
    print('connection from %s:%s closed' % addr)
while True:
    #接受一个新链接
    sock, addr = s.accept()
    #创建新的线程来处理tcp链接
    t = threading.Thread(target=tcplink, args=(sock, addr))
    t.start()

####客户端######
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
#建立连接
s.connect(('127.0.0.1', 9999))
#接受欢迎消息
print(s.recv(1024).decode('utf-8'))
for data in [b'Michael', b'Tracy', b'Sarah', b'ly', b'wj', b'lw']:
    s.send(data)
    print(s.recv(1024).decode('utf-8'))
s.send(b'exit')
s.close()

socket请求新浪主页

# 导入socket库:
import socket
# 创建一个socket: AF_INET指定使用IPv4协议，如果要用更先进的IPv6，就指定为AF_INET6
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# 建立连接:
s.connect(('www.sina.com.cn', 80))
# 发送数据:
s.send(b'GET / HTTP/1.1\r\nHost: www.sina.com.cn\r\nConnection: close\r\n\r\n')
# 接收数据:
buffer = []
while True:
    # 每次最多接收1k字节:
    d = s.recv(1024)
    if d:
        buffer.append(d)
    else:
        break
data = b''.join(buffer)
# 关闭连接:
s.close()
header, html = data.split(b'\r\n\r\n', 1)
print(header.decode('utf-8'))
# 把接收的数据写入文件:
with open('/Users/ly/Desktop/Python/project/sina.html', 'wb') as f:
    f.write(html)

GUI编程

from tkinter import *
import tkinter.messagebox as messagebox
class Application(Frame):
    def __init__(self, master = None):
        Frame.__init__(self, master)
        self.pack()
        self.createWidgets()
    def createWidgets(self):
        self.helloLabel = Label(self, text = 'Hello, word!')
        self.helloLabel.pack()
        self.quitButton = Button(self, text='Quit', command = self.quit)
        self.quitButton.pack()
app = Application()
app.master.title('hahhahahahah')
app.mainloop()
class Application(Frame):
    def __init__(self, master = None):
        Frame.__init__(self, master)
        self.pack()
        self.createWidgets()
    def createWidgets(self):
        self.nameInput = Entry(self)
        self.nameInput.pack()
        self.alertButton = Button(self, text = 'Hello', command = self.hello)
        self.alertButton.pack()
    def hello(self):
        name = self.nameInput.get() or 'word'
        messagebox.showinfo('Message', 'Hello, %s' % name)
app = Application()
app.master.title('hello')
app.mainloop()

chardet

import chardet
print(chardet.detect(b'hello, world'))
data = '离离原上草，一岁一枯荣'.encode('gbk')
print(chardet.detect(data))

pillow图片操作库

from PIL import Image, ImageFilter
#改变图片尺寸
im = Image.open('icon19.jpg')
w,h = im.size
print('Origin image size:%s X %s' % (w,h))
# 缩放到50%:
im.thumbnail((w//2,h//2))
print('Resize image to : %s X %s' % (w//2,h//2))
im.save('thumbnail.jpg', 'jpeg')
#图片模糊效果
im = Image.open('icon19.jpg')
im2 = im.filter(ImageFilter.BLUR)
im2 = im2.filter(ImageFilter.BLUR)
im2.save('blur2.jpg', 'jpeg')

生成字母验证码图片

from PIL import Image, ImageDraw, ImageFont, ImageFilter
import random
#随机字母
def rndChar():
    return chr(random.randint(65,90))
#随机颜色 浅色
def rndColor1():
    return (random.randint(64,255), random.randint(64,255), random.randint(64,255))
#随机颜色 深色
def rndColor2():
    return (random.randint(32,127), random.randint(32,127), random.randint(32,127))
width = 60 * 4
height = 60
image = Image.new('RGB', (width, height), (255, 255, 255))
font = ImageFont.truetype('Arial.ttf', 36)
draw = ImageDraw.Draw(image)
for x in range(width):
    for y in range(height):
        draw.point((x, y), fill = rndColor1())
for t in range(4):
    draw.text((60 * t + 10, 10), rndChar(), font = font, fill = rndColor2())
image = image.filter(ImageFilter.BLUR)
image.save('code.png','png')

psutil 运维

import psutil
print(psutil.cpu_count())# CPU逻辑数量
print(psutil.cpu_count(logical=False))# CPU物理核心
print(psutil.cpu_times())#统计CPU的用户／系统／空闲时间
# 实现类似top命令的CPU使用率，每秒刷新一次，累计10次
for i in range(10):
    print(psutil.cpu_percent(interval=1, percpu=True))
# 使用psutil获取物理内存和交换内存信息
print(psutil.virtual_memory())
print(psutil.swap_memory())
#通过psutil获取磁盘分区、磁盘使用率和磁盘IO信息
print(psutil.disk_partitions())
print(psutil.disk_usage('/'))
print(psutil.disk_io_counters())
print(psutil.net_io_counters())#获取网络读写字节／包的个数
print(psutil.net_if_addrs())# 获取网络接口信息
print(psutil.net_if_stats())# 获取网络接口状态
'''
net_connections() 你可能会得到一个AccessDenied错误，原因是psutil获取信息也是要走系统接口，
而获取网络连接信息需要root权限，这种情况下，可以退出Python交互环境，用sudo重新启动
'''
# print(psutil.net_connections())#当前网络连接信息
# print(psutil.pids())#所有进程ID
# print(psutil.Process(61))# 获取指定进程ID=61，其实就是当前Python交互环境
'''
>>> p = psutil.Process(3776) # 获取指定进程ID=3776，其实就是当前Python交互环境
>>> p.name() # 进程名称
'python3.6'
>>> p.exe() # 进程exe路径
'/Users/michael/anaconda3/bin/python3.6'
>>> p.cwd() # 进程工作目录
'/Users/michael'
>>> p.cmdline() # 进程启动的命令行
['python3']
>>> p.ppid() # 父进程ID
3765
>>> p.parent() # 父进程
<psutil.Process(pid=3765, name='bash') at 4503144040>
>>> p.children() # 子进程列表
[]
>>> p.status() # 进程状态
'running'
>>> p.username() # 进程用户名
'michael'
>>> p.create_time() # 进程创建时间
1511052731.120333
>>> p.terminal() # 进程终端
'/dev/ttys002'
>>> p.cpu_times() # 进程使用的CPU时间
pcputimes(user=0.081150144, system=0.053269812, children_user=0.0, children_system=0.0)
>>> p.memory_info() # 进程使用的内存
pmem(rss=8310784, vms=2481725440, pfaults=3207, pageins=18)
>>> p.open_files() # 进程打开的文件
[]
>>> p.connections() # 进程相关网络连接
[]
>>> p.num_threads() # 进程的线程数量
1
>>> p.threads() # 所有线程信息
[pthread(id=1, user_time=0.090318, system_time=0.062736)]
>>> p.environ() # 进程环境变量
{'SHELL': '/bin/bash', 'PATH': '/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:...', 'PWD': '/Users/michael', 'LANG': 'zh_CN.UTF-8', ...}
>>> p.terminate() # 结束进程
Terminated: 15 <-- 自己把自己结束了
'''

强烈推荐安装Anaconda，安装后，数十个常用的第三方模块就已经就绪

urllib

from urllib import request, parse
print('Login to weibo.cn...')
email = input('EmailOrPhone: ')
passwd = input('Password: ')
login_data = parse.urlencode([
    ('username', email),
    ('password', passwd),
    ('entry', 'mweibo'),
    ('client_id', ''),
    ('savestate', '1'),
    ('ec', ''),
    ('pagerefer', 'https://passport.weibo.cn/signin/welcome?entry=mweibo&r=http%3A%2F%2Fm.weibo.cn%2F')
])
req = request.Request('https://passport.weibo.cn/sso/login')
req.add_header('Origin', 'https://passport.weibo.cn')
req.add_header('User-Agent', 'Mozilla/6.0 (iPhone; CPU iPhone OS 8_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/8.0 Mobile/10A5376e Safari/8536.25')
req.add_header('Referer', 'https://passport.weibo.cn/signin/login?entry=mweibo&res=wel&wm=3349&r=http%3A%2F%2Fm.weibo.cn%2F')
with request.urlopen(req, data=login_data.encode('utf-8')) as f:
    print('Status:', f.status, f.reason)
    for k, v in f.getheaders():
        print('%s: %s' % (k, v))
    print('Data:', f.read().decode('utf-8'))

from urllib import request
with request.urlopen('https://api.douban.com/v2/book/2129650') as f:
    data = f.read()
    print('Status: ', f.status, f.reason)
    for k, v in f.getheaders():
        print('%s: %s' % (k, v))
    print('Data: ', data.decode('utf-8'))

contextlib

from contextlib import closing, contextmanager
如果一个对象没有实现上下文，我们就不能把它用于with语句。这个时候，可以用closing()来把该对象变为上下文对象。
@contextmanager这个decorator接受一个generator，用yield语句把with ... as var把变量输出出去，然后，with语句就可以正常地工作了
import itertools
count()会创建一个无限的迭代器，所以下面代码会打印出自然数序列
natuals = itertools.count(1)
for n in natuals:
    print(n)
cycle()会把传入的一个序列无限重复下去
cs = itertools.cycle('abc')
for c in cs:
    print(c)
repeat()负责把一个元素无限重复下去，不过如果提供第二个参数就可以限定重复次数
ns = itertools.repeat('A',11)
ns = itertools.repeat('A')
for n in ns:
    print(n)
natuals = itertools.count(1)
ns = itertools.takewhile(lambda x: x < 10, natuals)
print(list(ns))
chain()可以把一组迭代对象串联起来，形成一个更大的迭代器
for c in itertools.chain('ABC', '123', '~.,'):
    print(c)
groupby()把迭代器中相邻的重复元素挑出来放在一起
for key, group in itertools.groupby('AAABBBCCCCCCAA'):
    print(key,list(group))

hmac

import hmac
s = b'how to use hmac in python hashlib'
s1 = b'how to use hmac '
s2 = b'in python hashlib'
key = b'secret'
h = hmac.new(key, s, digestmod='MD5')
print(h.hexdigest())
h2 = hmac.new(key, s1, digestmod='MD5')
h2.update(s2)
print(h2.hexdigest())
# 9104c474395511d7d38784b690179b35
# 9104c474395511d7d38784b690179b35

hashlib

import hashlib
md5 = hashlib.md5()
# md5.update('how to use md5 in python hashlib'.encode('utf-8'))
# print(md5.hexdigest())
md5.update('how to use md5'.encode('utf-8'))
md5.update(' in python hashlib'.encode('utf-8'))
print(md5.hexdigest())
sha1 = hashlib.sha1()
sha1.update('how to use md5'.encode('utf-8'))
sha1.update(' in python hashlib'.encode('utf-8'))
print(sha1.hexdigest())

import hashlib
md5 = hashlib.md5()
sha1 = hashlib.sha1()
sha256 = hashlib.sha256()
md5.update('111111'.encode('utf-8'))#96e79218965eb72c92a549dd5a330112
md5.update('111111'.encode('utf-8'))#593c9b4a9390551d53e5cacf28ebd638
sha1.update('111111'.encode('utf-8'))#3d4f2bf07dc1be38b20cd6e46949a1071f9d0e3d
sha1.update('111111'.encode('utf-8'))#7ec8aa461c2c28be905e1dfb0be256a971aa6108
sha256.update('111111'.encode('utf-8'))#bcb15f821479b4d5772bd0ca866c00ad5f926e3580720659cc80d39c9d09802a
sha256.update('111111'.encode('utf-8'))#a18ac4e6fbd3fc024a07a21dafbac37d828ca8a04a0e34f368f1ec54e0d4fffb

base64

import base64, struct
def bmp_info(data):
    t = struct.unpack('<ccIIIIIIHH',data)
    if t[0] == b'B' and (t[1] == b'M' or t[1] == b'A'):
        return{
            'width' : t[6],
            'height' : t[7],
            'color' : t[9]
        }
    return{
        'width' : 0,
        'height' : 0,
        'color' : 0
    }
bmp_data = base64.b64decode('''
Qk1oAgAAAAAAADYAAAAoAAAAHAAAAAoAAAABABAAAAAAADICAAASCw
AAEgsAAAAAAAAAAAAA/3//f/9//3//f/9//3//f/9//3//f/9//3//
f/9//3//f/9//3//f/9//3//f/9//3//f/9//3//f/9/AHwAfAB8AH
wAfAB8AHwAfP9//3//fwB8AHwAfAB8/3//f/9/AHwAfAB8AHz/f/9/
/3//f/9//38AfAB8AHwAfAB8AHwAfAB8AHz/f/9//38AfAB8/3//f/
9//3//fwB8AHz/f/9//3//f/9//3//f/9/AHwAfP9//3//f/9/AHwA
fP9//3//fwB8AHz/f/9//3//f/9/AHwAfP9//3//f/9//3//f/9//38
AfAB8AHwAfAB8AHwAfP9//3//f/9/AHwAfP9//3//f/9//38AfAB8/3
//f/9//3//f/9//3//fwB8AHwAfAB8AHwAfAB8/3//f/9//38AfAB8/
3//f/9//3//fwB8AHz/f/9//3//f/9//3//f/9/AHwAfP9//3//f/9/
AHwAfP9//3//fwB8AHz/f/9/AHz/f/9/AHwAfP9//38AfP9//3//f/9/
AHwAfAB8AHwAfAB8AHwAfAB8/3//f/9/AHwAfP9//38AfAB8AHwAfAB8
AHwAfAB8/3//f/9//38AfAB8AHwAfAB8AHwAfAB8/3//f/9/AHwAfAB8
AHz/fwB8AHwAfAB8AHwAfAB8AHz/f/9//3//f/9//3//f/9//3//f/9/
/3//f/9//3//f/9//3//f/9//3//f/9//3//f/9//3//f/9//38AAA==''')
d = bmp_info(bmp_data[:30])
print(d['height'])

struct

import struct
n = 10240099
print(struct.pack('>I', n))
b1 = b'\xf0\xf0\xf0\xf0\x80\x80'
b2 = b'\x00\x9c@c'
print(struct.unpack('>I',b2))
print(struct.unpack('>IH',b1))

n = 10240099
b1 = (n & 0xff000000) >> 24
print(b1)
b2 = (n & 0xff0000) >> 16
print(b2)
b3 = (n & 0xff00) >> 8
print(b3)
b4 = (n & 0xff) 
print(b4)
bs = bytes([b1,b2,b3,b4])
print(bs)
print(bytes([b1]))
print(bytes([b2]))
print(bytes([b3]))
print(bytes([b4]))
print(bin(10240099))#0b 1001 1100 0100 0000 1100 011

import base64
print(base64.b64encode(b'1'))
print(base64.b64encode(b'abc'))
print(base64.b64decode('YWJj'))

collections

from collections import namedtuple, deque, defaultdict, OrderedDict, Counter
Circle = namedtuple('Circle',['x', 'y', 'r'])
circle = Circle(1,2,3)
print(circle.y)
q = deque(['a', 'b', 'c'])
q.append('x')
print(q)
q.appendleft('y')
print(q)
q.popleft()
print(q)
q.pop()
print(q)

dd = defaultdict(lambda: 'N/A')
dd['key1'] = 'nnn'
print(dd['key1'])
print(dd['key2'])

# OrderedDict的Key会按照插入的顺序排列，不是Key本身排序,可以实现一个FIFO（先进先出）的dict，
# 当容量超出限制时，先删除最早添加的Key
od = OrderedDict()
od['z'] = 1
od['y'] = 2
od['x'] = 3
print(od)

Counter是一个简单的计数器，例如，统计字符出现的个数
c = Counter()
for ch in 'merry christmas':
    c[ch] += 1
print(c)

datetime

from datetime import datetime, timedelta, timezone
dt = datetime(2017,12,25,10,40,46)
print(dt)
print(dt.timestamp())
t = 1514169646.0
print(datetime.fromtimestamp(t))
print(datetime.utcfromtimestamp(t))
cday = datetime.strptime('2017-12-25 11:05:21', '%Y-%m-%d %H:%M:%S')
print(cday)
now = datetime.now()
print(now.strftime('%a, %b %Y %d %H:%M'))
now = datetime.now()
now += timedelta(hours = 10)
print(now)
now += timedelta(days = 1, minutes = 20)
print(now)
now -= timedelta(seconds = 23)
print(now)
tz_utc_8 = timezone(timedelta(hours=8))
now = datetime.now()
print(now)
dt = now.replace(tzinfo=tz_utc_8)
print(dt)
# 拿到UTC时间，并强制设置时区为UTC+0:00:
utc_dt = datetime.utcnow().replace(tzinfo=timezone.utc)
print(utc_dt)
# astimezone()将转换时区为北京时间:
bj_dt = utc_dt.astimezone(timezone(timedelta(hours=8)))
print(bj_dt)
# astimezone()将转换时区为东京时间:
tokyo_dt = utc_dt.astimezone(timezone(timedelta(hours=9)))
print(tokyo_dt)
# astimezone()将bj_dt转换时区为东京时间:
tokyo_dt2 = bj_dt.astimezone(timezone(timedelta(hours=9)))
print(tokyo_dt2)
def str2Date(timeStr,timeZone):
    dt = datetime.strptime(timeStr, '%Y-%m-%d %H:%M:%S')
    dt2 = dt.astimezone(timezone(timedelta(hours=int(timeZone))))
    print(dt2)
    return dt2.timestamp()
ts = str2Date('2017-12-25 12:00:30','5')
print(ts)

正则表达式

import re
# list = re.split(r'\s+', 'a b    c')
list = re.split(r'[\s\,\;]+', 'a,,, b ;;   c,d')
print(list)

re_tel = re.compile(r'^(\d{3})-(\d{3,8})$')

groups = re_tel.match('000-123123').groups()
print(groups)

多线程

# 一个ThreadLocal变量虽然是全局变量，但每个线程都只能读写自己线程的独立副本，
# 互不干扰。ThreadLocal解决了参数在一个线程中各个函数之间互相传递的问题。

import time, threading
lock = threading.Lock()
def loop():
    try:
        lock.acquire()
        print('thread %s is runing...' % threading.current_thread().name)
        n = 0
        while n < 5:
            n += 1
            print('thread %s >>> %s' % (threading.current_thread().name, n))
            time.sleep(1)
        print('thread %s ended' % threading.current_thread().name)
    finally:
        lock.release()
    
print('thread %s is runing' % threading.current_thread().name)
t = threading.Thread(target=loop, name='LoopThread')
t.start()
t.join()
print('thread %s ended' % threading.current_thread().name)

from multiprocessing import Process, Queue
import os, time, random
def write(q):
    print('Process to write: %s' % os.getpid())
    for value in ['A', 'B', 'C']:
        print('Put %s to queue...' % value)
        q.put(value)
        time.sleep(random.random())

def read(q):
    print('Process to read: %s' % os.getpid())
    while True:
        value = q.get(True)
        print('Get %s from queue' % value)

if __name__ == '__main__':
    q = Queue()
    pw = Process(target=write,args=(q,))
    pr = Process(target=read,args=(q,))
    pw.start()
    pr.start()
    pw.join()
    pr.terminate()

import subprocess
print('$ nslookup www.python.org')
r = subprocess.call(['nslookup', 'www.qixiaofu.com'])
print('Wxit code:', r)
r = subprocess.call(['python3','/Users/ly/Desktop/ttt.py'])
print('$ nslookup')
p = subprocess.Popen(['nslookup'],stdin=subprocess.PIPE,stdout=subprocess.PIPE,stderr=subprocess.PIPE)
output,err = p.communicate(b'set q=mx\npython.org\nexit\n')
print(output.decode('utf-8'))
print('Exit code:',p.returncode)

from multiprocessing import Pool
import os,time,random
def long_time_task(name):
    print('Run task %s (%s)' % (name, os.getpid()))
    start = time.time()
    time.sleep(random.random() * 3)
    end = time.time()
    print('Task %s runs %0.2f seconds' % (name,(end - start)))

if __name__ == '__main__':
    print('Parent process %s' % os.getpid())
    p = Pool(4)#设置同时进行的进程数
    #p = Pool()#同时进行的进程数默认为cpu核数
    for i in range(10):
        p.apply_async(long_time_task, args=(i,))
    print('Waiting for all subprocesses done...')
    p.close()
    p.join()
    print('All subprocesses done')

from multiprocessing import Process
import os
def run_proc(name):
    print('Run child process %s (%s)' % (name,os.getpid()))

if __name__ == '__main__':
    print('Parent process is %s' % os.getpid)
    p = Process(target=run_proc, args=('test',))
    print('Child process will start.')
    p.start()
    print('----')
    p.join()
    print('Child process end')

os

import os
print(os.getpid())

pid = os.fork()
if pid == 0:
    print('child process(%s),parent process(%s)' % (os.getpid(), os.getppid()))
else:
    print('I(%s) create a child process(%s)' % (os.getpid(),pid))

json

import json 

class Student(object):
    def __init__(self, name, age, score):
        self.name = name
        self.age = age
        self.score = score
s = Student('Bob', 20, 88)
str = json.dumps(s,default=lambda obj:obj.__dict__)
print(str)
def dict2stu(d):
    return Student(d['name'],d['age'],d['score'])
json_str = '{"name": "Bob", "age": 20, "score": 88}'
s = json.loads(json_str, object_hook=dict2stu)
print(s)
print(s.__repr__)
obj = dict(name='小明', age=20)
s = json.dumps(obj, ensure_ascii=True) #{"name": "\u5c0f\u660e", "age": 20}
s = json.dumps(obj, ensure_ascii=False) #{"name": "小明", "age": 20}
print(s)
d = dict(name='ly', age=25, score=100)
s = json.dumps(d)
if isinstance(s,str):
    print('---')
print(s)

json_str = '{"name": "ly", "age": 25, "score": 100}'
d = json.loads(json_str)
if isinstance(d,dict):
    print('----')
print(d)

pickle

import pickle
'''
序列化存储
'''
d = dict(name='ly', age='25', score=100)
f = open('/Users/ly/Desktop/test.txt','wb')
pickle.dump(d,f)
f.close()
'''
反序列化
'''
f = open('/Users/ly/Desktop/test.txt','rb')
d = pickle.load(f)
f.close()
print(d)

import shutil
shutil.copyfile('/Users/ly/Desktop/test.txt','/Users/ly/Desktop/test333.txt')

import os
list = [x for x in os.listdir('.') if os.path.isdir(x)]
print(list)
list = [x for x in os.listdir('.') if os.path.isfile(x) and os.path.splitext(x)[1] == '.putty']
print(list)
print(os.path.split('/Users/ly/Desktop/test.txt')) #('/Users/ly/Desktop', 'test.txt')
print(os.path.splitext('/Users/ly/Desktop/test.txt')) #('/Users/ly/Desktop/test', '.txt')
print(os.path.splitext('/Users/ly/Desktop/test')) #('/Users/ly/Desktop/test', '')
print(os.path.abspath('.'))
print(os.path.join('/Users/ly', 'testdir'))
print(os.path.join('/Users/ly', 'testdir'))
os.mkdir('/Users/ly/testdir')
os.rmdir('/Users/ly/testdir')
print(os.name)
print(os.uname())
path = os.environ
print(path['PATH'])
print(path.get('TERM_SESSION_ID'))
print(path.get('x', 'default'))

from io import BytesIO
f = BytesIO()
f.write('中 wen'.encode('utf-8'))
print(f.getvalue())

from io import StringIO
f = StringIO('hello!\nHI\nword')
print(f.getvalue())
print('---')
for line in f.readlines():
    print(line)
f = StringIO()
f.write('hello')
f.write(' ')
f.write('word')
print(f.getvalue())

文件

# /Users/ly/Desktop/qixiaofu.png 
# /Users/ly/Desktop/test.txt

f = open('/Users/ly/Desktop/test.txt','w')
f.write('hahaha,hello ')
f.write('\n')
f.write('hahaha,hello ')
f.close()
with open('/Users/ly/Desktop/qixiaofu.png', 'rb') as f:
    print(f.read())

with open('/Users/ly/Desktop/test.txt', 'r') as f:
    print(f.read(100))

with open('/Users/ly/Desktop/test.txt', 'r') as f:
    for line in f.readlines():
        print(line)

try:
    f = open('/Users/ly/Desktop/test.txt','r')
    print(f.read())
finally:
    if f:
        f.close()

# # python3 -m pdb test.py 单步调试 ‘n’执行下一步
s = '0'
n = int(s)
print(n * 2)

functools

map()函数接收两个参数，一个是函数，一个是Iterable，map将传入的函数依次作用到序列的每个元素，并把结果作为新的Iterator返回。reduce把一个函数作用在一个序列[x1, x2, x3, ...]上，这个函数必须接收两个参数，reduce把结果继续和序列的下一个元素做累积计算

from functools import reduce

def str2num(s):
    return float(s)

def calc(exp):
    ss = exp.split('+')
    ns = map(str2num, ss)
    return reduce(lambda acc, x: acc + x, ns)

def main():
    r = calc('100 + 200 + 345')
    print('100 + 200 + 345 =', r)
    r = calc('99 + 88 + 7.6')
    print('99 + 88 + 7.6 =', r)

main()
eg:
reduce(f, [x1, x2, x3, x4]) = f(f(f(x1, x2), x3), x4)

枚举

from enum import Enum, unique

@unique
class WeekDay(Enum):
    Sun = 0
    Mon = 1
    Tue = 2
    Wed = 3
    Thu = 4
    Fri = 5
    Sat = 6

print(WeekDay.Thu)
print(WeekDay.Fri.value)        

class Chain(object):

    def __init__(self, path=''):
        self._path = path

    def __getattr__(self, path):
        return Chain('%s/%s' % (self._path, path))

    def __str__(self):
        return self._path

    __repr__ = __str__
        
l = Chain().status.user.timeline.list
print(l)

class Chain(object):

    def __init__(self, path=''):
        self._path = path

    def __getattr__(self, path):
        if path == 'users':
            return lambda name: Chain('%s/%s/:%s' % (self._path, path, name))
        else:
            return Chain('%s/%s' % (self._path, path))

    def __str__(self):
        return self._path

    __repr__ = __str__

l = Chain().status.user.timeline.list
print(l)
l2 = Chain().users('ly').repos
print(l2)

L = [('Bob', 75), ('Adam', 92), ('Bart', 66), ('Lisa', 88)]
def by_name(t):
    return t[1]
list = sorted(L,key=by_name)
list = sorted(['bob', 'about', 'Zoo', 'Credit'], key=str.lower, reverse=True)
print(list)

def intEqualInvertInt(num):
    num2 = int(str(num)[::-1])
    return num == num2

l = list(filter(intEqualInvertInt, [x for x in range(1000)]))
print(l)

L1 = ['adam', 'LISA', 'barT']
def transStr(str):
    str2 = ''
    for i in range(len(str)):
        if i == 0:
            str2 += str[i].upper()
        else:
            str2 += str[i].lower()
    return str2
L2 = list(map(transStr,L1))
print(L2)

杨辉三角形

def triangles(max):
    n = 0
    list = []
    while n < max:
        temp = []
        for num in range(len(list)):
            if num == 0:
                temp.append(list[num])
            else:
                temp.append(list[num-1] + list[num])
        temp.append(1)
        list = temp
        # print(list)
        yield list
        n += 1
    return 'done'
 
t = triangles(10)
for li in t:
    print(li)

L1 = ['Hello', 'World', 18, 'Apple', None]
L2 = [s.lower() for s in L1 if isinstance(s,str)]
print(L2)

import math 
print ('{:.0f}'.format(math.pi))

import sys
print("命令行参数:")
for i in sys.argv:
    print(i)

print("\n\npython 路径:", sys.path,'\n')

def outer():
    num = 10
    def inner():
        nonlocal num   # nonlocal关键字声明
        num = 100
        print(num)
    inner()
    print(num)
outer()


num = 1
def fun1():
    global num  # 需要使用 global 关键字声明
    print(num) 
    num = 123
    print(num)
fun1()

print(num)

list = [1,2,3,4]
it = iter(list)
print (next(it))
print (next(it),end='')
print ('11111')
for i in it:
    print(i)
for i in list:
    print(i)

import sys
def fibonacci(n):
    a,b,counter = 0,1,0
    while True:
        if (counter > n):
            return
        yield a
        a,b = b,a + b
        counter += 1
f = fibonacci(10)
print(f)
while True:
    try:
        print (next(f),end=' ')
    except StopIteration:
        sys.exit()