关于python:python-数据抓取三种方法

三种数据抓取的办法

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，获取指标网页的html，咱们以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)

*假如咱们须要爬取该网页中的国家名称和详情，咱们顺次应用这三种数据抓取的办法实现数据抓取。
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) #留神返回的是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)
#创立 beautifulsoup 对象
soup = BeautifulSoup(html,"html.parser")
#搜寻
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='')

运行后果：

最初，援用《用python写网络爬虫》中对三种办法的性能比照，如下图：

仅供参考。