三种数据抓取的方法

*利用之前构建的下载网页函数，获取目标网页的html，我们以https://guojiadiqu.bmcx.com/AFG__guojiayudiqu/为例，获取html。

from get_html import download

url = 'https://guojiadiqu.bmcx.com/AFG__guojiayudiqu/' page_content = download(url)

*假设我们需要爬取该网页中的国家名称和概况，我们依次使用这三种数据抓取的方法实现数据抓取。
1.正则表达式

from get_html import download import re

url = 'https://guojiadiqu.bmcx.com/AFG__guojiayudiqu/' page_content = download(url) country = re.findall('class="h2dabiaoti">(.*?)</h2>', page_content) #注意返回的是list survey_data = re.findall('<tr><td bgcolor="#FFFFFF" id="wzneirong">(.*?)</td></tr>', page_content) survey_info_list = re.findall('<p>　　(.*?)</p>', survey_data[0]) survey_info = ''.join(survey_info_list) print(country[0],survey_info)

2.BeautifulSoup（bs4）

from get_html import download from bs4 import BeautifulSoup

url = 'https://guojiadiqu.bmcx.com/AFG__guojiayudiqu/' html = download(url) #创建 beautifulsoup 对象 soup = BeautifulSoup(html,"html.parser") #搜索 country = soup.find(attrs={'class':'h2dabiaoti'}).text survey_info = soup.find(attrs={'id':'wzneirong'}).text print(country,survey_info)

3.lxml

from get_html import download from lxml import etree #解析树

url = 'https://guojiadiqu.bmcx.com/AFG__guojiayudiqu/' page_content = download(url) selector = etree.HTML(page_content)#可进行xpath解析 country_select = selector.xpath('//*[@id="main_content"]/h2') #返回列表 for country in country_select: print(country.text) survey_select = selector.xpath('//*[@id="wzneirong"]/p') for survey_content in survey_select: print(survey_content.text,end='')

运行结果：

最后，引用《用python写网络爬虫》中对三种方法的性能对比，如下图：

仅供参考。