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1、4.2scrapy中查找HTML元素(1)在前面我们已经知道使用BeautifulSoup能查找HTML中的元素，scrapy中也有强大的查找HTML元素的功能，那就是使用xpath方法。xpath方法使用XPath语法，比BeautifulSoup的select要灵活而且速度快。例4-2-1:使用xpath查找HTML中的元素fromscrapy.selectorimportSelectorhtmlText='''
HarryPotter29.99<2、/book>LearningXML39.95
'''selector=Selector(text=htmlText)print(type(selector));print(selector)s=selector.xpath("//title")print(type(s))print(s)程序结果：class'scrapy.selector.unified.Selector'>
3、l>
[,](1)fromscrapy.selectorimportSelector从scrapy中引入Selector类，这个类就是选择查找类。(2)sel4、ector=Selector(text=htmlText)使用htmlText的文字建立Selector类，就是装载HTML文档，文档装载后就形成一个Selector对象，就可以使用xpath查找元素。(3)print(type(selector)可看到selector是一个类型为scrapy.selector.unified.Selector，这个类型是一个有xpath方法的类型。((4)s=selector.xpath("//title")这个方法在文档中查找所有的
的元素，其中"//"表示文档中的任何位置。一般地：selector.xpath("//tagName")</p><p>5、表示在权文档中搜索<tagName>的tags，形成一个Selector的列表。(5)print(type(s))由于<title>有两个元素，因此我们看到这是一个scrapy.selector.unified.SelectorList类，类似scrapy.selector.unified.Selector的列表。(6)print(s)我们看到s包含两个Selector对象，一个是<Selectorxpath='//title'data='<titlelang="eng">HarryPotter'>，另外一个是。由此可见一般selector搜索一个的HTML元素的方法是：selector.xpath("//tagName")在装载HTML文档后selector=Selector(text=htmlText)得到的selector是对应全文档顶层的元素的，其中"//"表示全文档搜索，结果是一个Selector的列表，哪怕只有一个元素也成一个列表，例如：se7、lector.xpath("//body")搜索到
元素，结果是一个Selector的列表，包含一个Selector元素；selector.xpath("//title")搜索到两个元素，结果是Selector的列表，包含2个Selector元素；selector.xpath("//book")搜索到两个<book>元素，结果是Selector的列表，包含2个Selector元素；4.2scrapy中查找HTML元素(2</p> </div>
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