目录
Python网络爬虫与信息提取
- 淘宝商品比价定向爬虫
  - - 目标获取淘宝搜索页面的信息
    - 理解淘宝的搜索接口翻页的处理
    - 技术路线requests-refootnote
  - 代码如下
- 股票数据定向爬虫
  - 列表内容
  - 爬取网站原则
  - 代码如下
  - 代码优化

Python网络爬虫与信息提取

淘宝商品比价定向爬虫
股票数据定向爬虫

1. 淘宝商品比价定向爬虫

功能描述

目标：获取淘宝搜索页面的信息

理解：淘宝的搜索接口翻页的处理

技术路线：requests-re[^footnote].

代码如下：

#CrowTaobaoPrice.py
import requests
import redef getHTMLText(url):try:r = requests.get(url, timeout=30)r.raise_for_status()r.encoding = r.apparent_encodingreturn r.textexcept:return ""def parsePage(ilt, html):try:plt = re.findall(r'\"view_price\"\:\"[\d\.]*\"',html)tlt = re.findall(r'\"raw_title\"\:\".*?\"',html)for i in range(len(plt)):price = eval(plt[i].split(':')[1])title = eval(tlt[i].split(':')[1])ilt.append([price , title])except:print("")def printGoodsList(ilt):tplt = "{:4}\t{:8}\t{:16}"print(tplt.format("序号", "价格", "商品名称"))count = 0for g in ilt:count = count + 1print(tplt.format(count, g[0], g[1]))def main():goods = '书包'depth = 3start_url = 'https://s.taobao.com/search?q=' + goodsinfoList = []for i in range(depth):try:url = start_url + '&s=' + str(44*i)html = getHTMLText(url)parsePage(infoList, html)except:continueprintGoodsList(infoList)main()

流程图：
步骤1：提交商品搜索请求，循环获取页面
步骤2：对于每个页面，提取商品名称和价格信息
步骤3：将信息输出到屏幕上

Created with Raphaël 2.1.0开始提交商品搜索请求，循环获取页面对于每个页面，提取商品名称和价格信息将信息输出到屏幕上结束

2. 股票数据定向爬虫

1. 列表内容

功能描述
目标：获取上交所和深交所所有股票的名称和交易信息
输出：保存到文件中
技术路线：requests-bs4-re

新浪股票：http://finance.sina.com.cn/stock/
百度股票：https://gupiao.baidu.com/stock/

2.爬取网站原则

选取原则：股票信息静态存在于HTML页面中，非js代码生成，没有Robots协议限制
选取方法：浏览器F12，源代码查看等
选取心态：不要纠结于某个网站，多找信息源尝试

程序结构如下

Created with Raphaël 2.1.0开始步骤1：从东方财富网获取股票列表步骤2：根据股票列表逐个到百度股票获取个股信息步骤3：将结果存储到文件结束

代码如下

#CrawBaiduStocksA.py
import requests
from bs4 import BeautifulSoup
import traceback
import redef getHTMLText(url):try:r = requests.get(url)r.raise_for_status()r.encoding = r.apparent_encodingreturn r.textexcept:return ""def getStockList(lst, stockURL):html = getHTMLText(stockURL)soup = BeautifulSoup(html, 'html.parser') a = soup.find_all('a')for i in a:try:href = i.attrs['href']lst.append(re.findall(r"[s][hz]\d{6}", href)[0])except:continuedef getStockInfo(lst, stockURL, fpath):for stock in lst:url = stockURL + stock + ".html"html = getHTMLText(url)try:if html=="":continueinfoDict = {}soup = BeautifulSoup(html, 'html.parser')stockInfo = soup.find('div',attrs={'class':'stock-bets'})name = stockInfo.find_all(attrs={'class':'bets-name'})[0]infoDict.update({'股票名称': name.text.split()[0]})keyList = stockInfo.find_all('dt')valueList = stockInfo.find_all('dd')for i in range(len(keyList)):key = keyList[i].textval = valueList[i].textinfoDict[key] = valwith open(fpath, 'a', encoding='utf-8') as f:f.write( str(infoDict) + '\n' )except:traceback.print_exc()continuedef main():stock_list_url = 'http://quote.eastmoney.com/stocklist.html'stock_info_url = 'https://gupiao.baidu.com/stock/'output_file = 'D:/BaiduStockInfo.txt'slist=[]getStockList(slist, stock_list_url)getStockInfo(slist, stock_info_url, output_file)main()

代码优化

1.编码识别优化
2.增加动态进度显示

优化后代码如下

import requests
from bs4 import BeautifulSoup
import traceback
import redef getHTMLText(url, code="utf-8"):try:r = requests.get(url)r.raise_for_status()r.encoding = codereturn r.textexcept:return ""def getStockList(lst, stockURL):html = getHTMLText(stockURL, "GB2312")soup = BeautifulSoup(html, 'html.parser') a = soup.find_all('a')for i in a:try:href = i.attrs['href']lst.append(re.findall(r"[s][hz]\d{6}", href)[0])except:continuedef getStockInfo(lst, stockURL, fpath):count = 0for stock in lst:url = stockURL + stock + ".html"html = getHTMLText(url)try:if html=="":continueinfoDict = {}soup = BeautifulSoup(html, 'html.parser')stockInfo = soup.find('div',attrs={'class':'stock-bets'})name = stockInfo.find_all(attrs={'class':'bets-name'})[0]infoDict.update({'股票名称': name.text.split()[0]})keyList = stockInfo.find_all('dt')valueList = stockInfo.find_all('dd')for i in range(len(keyList)):key = keyList[i].textval = valueList[i].textinfoDict[key] = valwith open(fpath, 'a', encoding='utf-8') as f:f.write( str(infoDict) + '\n' )count = count + 1print("\r当前进度: {:.2f}%".format(count*100/len(lst)),end="")except:count = count + 1print("\r当前进度: {:.2f}%".format(count*100/len(lst)),end="")continuedef main():stock_list_url = 'http://quote.eastmoney.com/stocklist.html'stock_info_url = 'https://gupiao.baidu.com/stock/'output_file = 'D:/BaiduStockInfo.txt'slist=[]getStockList(slist, stock_list_url)getStockInfo(slist, stock_info_url, output_file)main()

来自
Python网络爬虫与信息提取
中国大学mooc
http://www.icourse163.org/learn/BIT-1001870001?tid=1001962001#/learn/content?type=detail&id=1002699548&cid=1003101008