Python网络爬虫与信息提取（中国大学mooc）

目录

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 re

def getHTMLText(url):
try:
r = requests.get(url, timeout=30)
r.raise_for_status()
r.encoding = r.apparent_encoding
return r.text
except:
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 = 0
for g in ilt:
count = count + 1
print(tplt.format(count, g[0], g[1]))

def main():
goods = '书包'
depth = 3
start_url = 'https://s.taobao.com/search?q=' + goods
infoList = []
for i in range(depth):
try:
url = start_url + '&s=' + str(44*i)
html = getHTMLText(url)
parsePage(infoList, html)
except:
continue
printGoodsList(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 re

def getHTMLText(url):
try:
r = requests.get(url)
r.raise_for_status()
r.encoding = r.apparent_encoding
return r.text
except:
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:
continue

def getStockInfo(lst, stockURL, fpath):
for stock in lst:
url = stockURL + stock + ".html"
html = getHTMLText(url)
try:
if html=="":
continue
infoDict = {}
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].text
val = valueList[i].text
infoDict[key] = val

with open(fpath, 'a', encoding='utf-8') as f:
f.write( str(infoDict) + '\n' )
except:
traceback.print_exc()
continue

def 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 re

def getHTMLText(url, code="utf-8"):
try:
r = requests.get(url)
r.raise_for_status()
r.encoding = code
return r.text
except:
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:
continue

def getStockInfo(lst, stockURL, fpath):
count = 0
for stock in lst:
url = stockURL + stock + ".html"
html = getHTMLText(url)
try:
if html=="":
continue
infoDict = {}
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].text
val = valueList[i].text
infoDict[key] = val

with open(fpath, 'a', encoding='utf-8') as f:
f.write( str(infoDict) + '\n' )
count = count + 1
print("\r当前进度: {:.2f}%".format(count*100/len(lst)),end="")
except:
count = count + 1
print("\r当前进度: {:.2f}%".format(count*100/len(lst)),end="")
continue

def 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