python抓取网页数据的三种方法

一、正则表达式提取网页内容

解析效率：正则表达式>lxml>beautifulsoup代码：

import reimport urllib2 urllist = 'http://example.webscraping.com/places/default/view/United-Kingdom-239' html = urllib2.urlopen(urllist).read()num = re.findall('<td class="w2p_fw">(.*?)</td>',html)print numprint "num[1]: ",num[1]

二、BeautifulSoup方法提取网页内容代码如下：

from bs4 import BeautifulSoupimport urllib2 urllist = 'http://example.webscraping.com/places/default/view/United-Kingdom-239' html = urllib2.urlopen(urllist).read()#把html格式进行确定和纠正soup = BeautifulSoup(html,'html.parser')#找出tr标签中id属性为places_area__row的内容，如果把find改成findall函数则会把匹配所#有的内容显示出来，find函数只匹配第一次匹配的内容。tr = soup.find('tr',attrs={'id':'places_area__row'})td = tr.find('td',attrs={'class':'w2p_fw'})#取出标签内容area = td.textprint "area: ",area

三、lxmllxml库功能和使用类似BeautifulSoup库，不过lxml解析速度比beautifulsoup快。代码：

import lxml.htmlimport urllib2 urllist = 'http://example.webscraping.com/places/default/view/United-Kingdom-239' html = urllib2.urlopen(urllist).read()tree = lxml.html.fromstring(html)td = tree.cssselect('tr#places_area__row > td.w2p_fw')[0]area = td.text_content()print area