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今天分享幾段工作生活中常用的代碼，都是最為基礎(chǔ)的功能和操作，而且大多還都是出現(xiàn)頻率比較高的，很多都是可以拿來直接使用或者簡(jiǎn)單修改就可以放到自己的項(xiàng)目當(dāng)中

日期生成

很多時(shí)候我們需要批量生成日期，方法有很多，這里分享兩段代碼

獲取過去 N 天的日期

import?datetime

def?get_nday_list(n):
????before_n_days?=?[]
????for?i?in?range(1,?n?+?1)[::-1]:
????????before_n_days.append(str(datetime.date.today()?-?datetime.timedelta(days=i)))
????return?before_n_days

a?=?get_nday_list(30)
print(a)

Output:

['2021-12-23', '2021-12-24', '2021-12-25', '2021-12-26', '2021-12-27', '2021-12-28', '2021-12-29', '2021-12-30', '2021-12-31', '2022-01-01', '2022-01-02', '2022-01-03', '2022-01-04', '2022-01-05', '2022-01-06', '2022-01-07', '2022-01-08', '2022-01-09', '2022-01-10', '2022-01-11', '2022-01-12', '2022-01-13', '2022-01-14', '2022-01-15', '2022-01-16', '2022-01-17', '2022-01-18', '2022-01-19', '2022-01-20', '2022-01-21']

生成一段時(shí)間區(qū)間內(nèi)的日期

import?datetime

def?create_assist_date(datestart?=?None,dateend?=?None):
????#?創(chuàng)建日期輔助表

????if?datestart?is?None:
????????datestart?=?'2016-01-01'
????if?dateend?is?None:
????????dateend?=?datetime.datetime.now().strftime('%Y-%m-%d')

????#?轉(zhuǎn)為日期格式
????datestart=datetime.datetime.strptime(datestart,'%Y-%m-%d')
????dateend=datetime.datetime.strptime(dateend,'%Y-%m-%d')
????date_list?=?[]
????date_list.append(datestart.strftime('%Y-%m-%d'))
????while?datestart????????#?日期疊加一天
????????datestart+=datetime.timedelta(days=+1)
????????#?日期轉(zhuǎn)字符串存入列表
????????date_list.append(datestart.strftime('%Y-%m-%d'))
????return?date_list

d_list?=?create_assist_date(datestart='2021-12-27',?dateend='2021-12-30')
d_list

Output:

['2021-12-27', '2021-12-28', '2021-12-29', '2021-12-30']

保存數(shù)據(jù)到CSV

保存數(shù)據(jù)到 CSV 是太常見的操作了，分享一段我個(gè)人比較喜歡的寫法

def?save_data(data,?date):
????if?not?os.path.exists(r'2021_data_%s.csv'?%?date):
????????with?open("2021_data_%s.csv"?%?date,?"a+",?encoding='utf-8')?as?f:
????????????f.write("標(biāo)題,熱度,時(shí)間,url\n")
????????????for?i?in?data:
????????????????title?=?i["title"]
????????????????extra?=?i["extra"]
????????????????time?=?i['time']
????????????????url?=?i["url"]
????????????????row?=?'{},{},{},{}'.format(title,extra,time,url)
????????????????f.write(row)
????????????????f.write('\n')
????else:
????????with?open("2021_data_%s.csv"?%?date,?"a+",?encoding='utf-8')?as?f:
????????????for?i?in?data:
????????????????title?=?i["title"]
????????????????extra?=?i["extra"]
????????????????time?=?i['time']
????????????????url?=?i["url"]
????????????????row?=?'{},{},{},{}'.format(title,extra,time,url)
????????????????f.write(row)
????????????????f.write('\n')

帶背景顏色的 Pyecharts

Pyecharts 作為 Echarts 的優(yōu)秀 Python 實(shí)現(xiàn)，受到眾多開發(fā)者的青睞，用 Pyecharts 作圖時(shí)，使用一個(gè)舒服的背景也會(huì)給我們的圖表增色不少

以餅圖為例，通過添加 JavaScript 代碼來改變背景顏色

def?pie_rosetype(data)?->?Pie:
????background_color_js?=?(
????"new?echarts.graphic.LinearGradient(0,?0,?0,?1,?"
????"[{offset:?0,?color:?'#c86589'},?{offset:?1,?color:?'#06a7ff'}],?false)"
)
????c?=?(
????????Pie(init_opts=opts.InitOpts(bg_color=JsCode(background_color_js)))
????????.add(
????????????"",
????????????data,
????????????radius=["30%",?"75%"],
????????????center=["45%",?"50%"],
????????????rosetype="radius",
????????????label_opts=opts.LabelOpts(formatter="{b}:?{c}"),
????????)
????????.set_global_opts(title_opts=opts.TitleOpts(title=""),
????????????????????????)
????)
????return?c

requests 庫(kù)調(diào)用

據(jù)統(tǒng)計(jì)，requests 庫(kù)是 Python 家族里被引用的最多的第三方庫(kù)，足見其江湖地位之高大！

發(fā)送 GET 請(qǐng)求

import?requests


headers?=?{
????'user-agent':?'Mozilla/5.0?(Windows?NT?10.0;?Win64;?x64)?AppleWebKit/537.36?(KHTML,?like?Gecko)?Chrome/96.0.4664.110?Safari/537.36',
??'cookie':?'some_cookie'
}
response?=?requests.request("GET",?url,?headers=headers)

發(fā)送 POST 請(qǐng)求

import?requests


payload={}
files=[]
headers?=?{
????'user-agent':?'Mozilla/5.0?(Windows?NT?10.0;?Win64;?x64)?AppleWebKit/537.36?(KHTML,?like?Gecko)?Chrome/96.0.4664.110?Safari/537.36',
??'cookie':?'some_cookie'
}
response?=?requests.request("POST",?url,?headers=headers,?data=payload,?files=files)

根據(jù)某些條件循環(huán)請(qǐng)求，比如根據(jù)生成的日期

def?get_data(mydate):
????date_list?=?create_assist_date(mydate)
????url?=?"https://test.test"
????files=[]
????headers?=?{
????????'user-agent':?'Mozilla/5.0?(Windows?NT?10.0;?Win64;?x64)?AppleWebKit/537.36?(KHTML,?like?Gecko)?Chrome/96.0.4664.110?Safari/537.36',
????????'cookie':?''
????????}
????for?d?in?date_list:
????????payload={'p':?'10',
????????'day':?d,
????????'nodeid':?'1',
????????'t':?'itemsbydate',
????????'c':?'node'}
????????for?i?in?range(1,?100):
????????????payload['p']?=?str(i)
????????????print("get?data?of?%s?in?page?%s"?%?(d,?str(i)))
????????????response?=?requests.request("POST",?url,?headers=headers,?data=payload,?files=files)
????????????items?=?response.json()['data']['items']
????????????if?items:
????????????????save_data(items,?d)
????????????else:
????????????????break

Python 操作各種數(shù)據(jù)庫(kù)

操作 Redis

連接 Redis

import?redis


def?redis_conn_pool():
????pool?=?redis.ConnectionPool(host='localhost',?port=6379,?decode_responses=True)
????rd?=?redis.Redis(connection_pool=pool)
????return?rd

寫入 Redis

from?redis_conn?import?redis_conn_pool


rd?=?redis_conn_pool()
rd.set('test_data',?'mytest')

操作 MongoDB

連接 MongoDB

from?pymongo?import?MongoClient


conn?=?MongoClient("mongodb://%s:%s@ipaddress:49974/mydb"?%?('username',?'password'))
db?=?conn.mydb
mongo_collection?=?db.mydata

批量插入數(shù)據(jù)

res?=?requests.get(url,?params=query).json()
commentList?=?res['data']['commentList']
mongo_collection.insert_many(commentList)

操作 MySQL

連接 MySQL

import?MySQLdb

#?打開數(shù)據(jù)庫(kù)連接
db?=?MySQLdb.connect("localhost",?"testuser",?"test123",?"TESTDB",?charset='utf8'?)

#?使用cursor()方法獲取操作游標(biāo)?
cursor?=?db.cursor()

執(zhí)行 SQL 語句

#?使用?execute?方法執(zhí)行?SQL?語句
cursor.execute("SELECT?VERSION()")

#?使用?fetchone()?方法獲取一條數(shù)據(jù)
data?=?cursor.fetchone()

print?"Database?version?:?%s?"?%?data

#?關(guān)閉數(shù)據(jù)庫(kù)連接
db.close()

Output:

Database version : 5.0.45

本地文件整理

整理文件涉及需求的比較多，這里分享的是將本地多個(gè) CSV 文件整合成一個(gè)文件

import?pandas?as?pd
import?os


df_list?=?[]
for?i?in?os.listdir():
????if?"csv"?in?i:
????????day?=?i.split('.')[0].split('_')[-1]
????????df?=?pd.read_csv(i)
????????df['day']?=?day
????????df_list.append(df)
df?=?pd.concat(df_list,?axis=0)
df.to_csv("total.txt",?index=0)

多線程代碼

多線程也有很多實(shí)現(xiàn)方式，我們選擇自己最為熟悉順手的方式即可

import?threading
import?time

exitFlag?=?0

class?myThread?(threading.Thread):
????def?__init__(self,?threadID,?name,?delay):
????????threading.Thread.__init__(self)
????????self.threadID?=?threadID
????????self.name?=?name
????????self.delay?=?delay
????def?run(self):
????????print?("開始線程："?+?self.name)
????????print_time(self.name,?self.delay,?5)
????????print?("退出線程："?+?self.name)

def?print_time(threadName,?delay,?counter):
????while?counter:
????????if?exitFlag:
????????????threadName.exit()
????????time.sleep(delay)
????????print?("%s:?%s"?%?(threadName,?time.ctime(time.time())))
????????counter?-=?1

#?創(chuàng)建新線程
thread1?=?myThread(1,?"Thread-1",?1)
thread2?=?myThread(2,?"Thread-2",?2)

#?開啟新線程
thread1.start()
thread2.start()
thread1.join()
thread2.join()
print?("退出主線程")

異步編程代碼

異步爬取網(wǎng)站

import?asyncio
import?aiohttp
import?aiofiles

async?def?get_html(session,?url):
????try:
????????async?with?session.get(url=url,?timeout=8)?as?resp:
????????????if?not?resp.status?//?100?==?2:
????????????????print(resp.status)
????????????????print("爬取",?url,?"出現(xiàn)錯(cuò)誤")
????????????else:
????????????????resp.encoding?=?'utf-8'
????????????????text?=?await?resp.text()
????????????????return?text
????except?Exception?as?e:
????????print("出現(xiàn)錯(cuò)誤",?e)
????????await?get_html(session,?url)

使用異步請(qǐng)求之后，對(duì)應(yīng)的文件保存也需要使用異步，即是一處異步，處處異步

async?def?download(title_list,?content_list):
????async?with?aiofiles.open('{}.txt'.format(title_list[0]),?'a',
?????????????????????????????encoding='utf-8')?as?f:
????????await?f.write('{}'.format(str(content_list)))

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