Python中怎么定时执行网站爬虫

Python中怎么定时执行网站爬虫,针对这个问题,这篇文章详细介绍了相对应的分析和解答,希望可以帮助更多想解决这个问题的小伙伴找到更简单易行的方法。

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编写爬虫代码

编写一个爬虫程序,使用requestsbeautifulsoup4包爬取和解析Yahoo!股市-上市成交价排行与Yahoo!股市-上柜成交价排行的资料,再利用pandas包将解析后的展示出来。

import datetime
import requests
from bs4 import BeautifulSoup
import pandas as pd

def get_price_ranks():
   current_dt = datetime.datetime.now().strftime("%Y-%m-%d %X")
   current_dts = [current_dt for _ in range(200)]
   stock_types = ["tse", "otc"]
   price_rank_urls = ["https://tw.stock.yahoo.com/d/i/rank.php?t=pri&e={}&n=100".format(st) for st in stock_types]
   tickers = []
   stocks = []
   prices = []
   volumes = []
   mkt_values = []
   ttl_steps = 10*100
   each_step = 10
   for pr_url in price_rank_urls:
       r = requests.get(pr_url)
       soup = BeautifulSoup(r.text, 'html.parser')
       ticker = [i.text.split()[0] for i in soup.select(".name a")]
       tickers += ticker
       stock = [i.text.split()[1] for i in soup.select(".name a")]
       stocks += stock
       price = [float(soup.find_all("td")[2].find_all("td")[i].text) for i in range(5, 5+ttl_steps, each_step)]
       prices += price
       volume = [int(soup.find_all("td")[2].find_all("td")[i].text.replace(",", "")) for i in range(11, 11+ttl_steps, each_step)]
       volumes += volume
       mkt_value = [float(soup.find_all("td")[2].find_all("td")[i].text)*100000000 for i in range(12, 12+ttl_steps, each_step)]
       mkt_values += mkt_value
   types = ["上市" for _ in range(100)] + ["上柜" for _ in range(100)]
   ky_registered = [True if "KY" in st else False for st in stocks]
   df = pd.DataFrame()
   df["scrapingTime"] = current_dts
   df["type"] = types
   df["kyRegistered"] = ky_registered
   df["ticker"] = tickers
   df["stock"] = stocks
   df["price"] = prices
   df["volume"] = volumes
   df["mktValue"] = mkt_values
   return df

price_ranks = get_price_ranks()
print(price_ranks.shape)

这个的结果展示为

## (200, 8)

接下来我们利用pandas进行前几行展示

price_ranks.head()
price_ranks.tail()

Python中怎么定时执行网站爬虫

Python中怎么定时执行网站爬虫

接下来我们就开始往服务器上部署

对于服务器的选择,环境配置不在本课的讨论范围之内,我们主要是要讲一下怎么去设置定时任务。

接下来我们改造一下代码,改造成结果有sqlite存储。

import datetime
import requests
from bs4 import BeautifulSoup
import pandas as pd
import sqlite3

def get_price_ranks():
   current_dt = datetime.datetime.now().strftime("%Y-%m-%d %X")
   current_dts = [current_dt for _ in range(200)]
   stock_types = ["tse", "otc"]
   price_rank_urls = ["https://tw.stock.yahoo.com/d/i/rank.php?t=pri&e={}&n=100".format(st) for st in stock_types]
   tickers = []
   stocks = []
   prices = []
   volumes = []
   mkt_values = []
   ttl_steps = 10*100
   each_step = 10
   for pr_url in price_rank_urls:
       r = requests.get(pr_url)
       soup = BeautifulSoup(r.text, 'html.parser')
       ticker = [i.text.split()[0] for i in soup.select(".name a")]
       tickers += ticker
       stock = [i.text.split()[1] for i in soup.select(".name a")]
       stocks += stock
       price = [float(soup.find_all("td")[2].find_all("td")[i].text) for i in range(5, 5+ttl_steps, each_step)]
       prices += price
       volume = [int(soup.find_all("td")[2].find_all("td")[i].text.replace(",", "")) for i in range(11, 11+ttl_steps, each_step)]
       volumes += volume
       mkt_value = [float(soup.find_all("td")[2].find_all("td")[i].text)*100000000 for i in range(12, 12+ttl_steps, each_step)]
       mkt_values += mkt_value
   types = ["上市" for _ in range(100)] + ["上櫃" for _ in range(100)]
   ky_registered = [True if "KY" in st else False for st in stocks]
   df = pd.DataFrame()
   df["scrapingTime"] = current_dts
   df["type"] = types
   df["kyRegistered"] = ky_registered
   df["ticker"] = tickers
   df["stock"] = stocks
   df["price"] = prices
   df["volume"] = volumes
   df["mktValue"] = mkt_values
   return df

price_ranks = get_price_ranks()
conn = sqlite3.connect('/home/ubuntu/yahoo_stock.db')
price_ranks.to_sql("price_ranks", conn, if_exists="append", index=False)

接下来如果我们让他定时启动,那么,我们需要linux的crontab命令:

如果我们要设置每天的 9:30 到 16:30 之间每小时都执行一次

那么我们只需要先把文件命名为price_rank_scraper.py

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