介绍python 数据抓取三种方法

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三种数据抓取的方法u9d少儿编程网-Scratch_Python_教程_免费儿童编程学习平台

正则表达式（re库）BeautifulSoup（bs4）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/AFG__guojiayudiqu/为例，获取html。u9d少儿编程网-Scratch_Python_教程_免费儿童编程学习平台

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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u9d少儿编程网-Scratch_Python_教程_免费儿童编程学习平台

from get_html import downloadimport 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listsurvey_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）u9d少儿编程网-Scratch_Python_教程_免费儿童编程学习平台

from get_html import downloadfrom 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'}).textprint(country,survey_info)

3.lxmlu9d少儿编程网-Scratch_Python_教程_免费儿童编程学习平台

from get_html import downloadfrom 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：

**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。u9d少儿编程网-Scratch_Python_教程_免费儿童编程学习平台

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