python 数据抓取三种方法

三种数据抓取的方法

  1. 正则表达式(re库)
  2. BeautifulSoup(bs4)
  3. lxml
    *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/A...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">(.*?)', page_content) #注意返回的是list
survey_data = re.findall('(.*?)', page_content)
survey_info_list = re.findall('

  (.*?)

', 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:
python 数据抓取三种方法_第1张图片
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:
python 数据抓取三种方法_第2张图片
仅供参考。

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