xpath:如何编写条件xpath？

Question

我正试图从以下两页中提取价格信息：

http://jujumarts.com/mobiles-accessories-smartphones-wildfire-sdarkgrey-p-551.html http://jujumarts.com/computers-accessories-transcend-500gb-portable-storejet-25d2-p-2616.html

xpath1 = //span[@class='productSpecialPrice']//text()
xpath2 = //div[@class='proDetPrice']//text()

到目前为止，我已经编写了python代码，如果成功，返回xpath1的结果，否则执行第二个。我有一种感觉，仅仅在xpath中实现这个逻辑是可能的，有人能告诉我如何实现吗？

Answer 1

使用|表示union

xpath3 = "//span[@class='productSpecialPrice']//text()|//div[@class='proDetPrice']//text()"

这并不是你所要求的，但我认为它可以纳入一个可行的解决方案中。

来自XPath (1.0版)规范

\\运算符计算其操作数的联合，该操作数必须是节点集。

例如,

import lxml.html as LH

urls = [
    'http://jujumarts.com/mobiles-accessories-smartphones-wildfire-sdarkgrey-p-551.html',
    'http://jujumarts.com/computers-accessories-transcend-500gb-portable-storejet-25d2-p-2616.html'
    ]

xpaths = [
    "//span[@class='productSpecialPrice']//text()",
    "//div[@class='proDetPrice']//text()",
    "//span[@class='productSpecialPrice']//text()|//div[@class='proDetPrice']//text()"
    ]
for url in urls:
    doc = LH.parse(url)
    for xpath in xpaths:
        print(doc.xpath(xpath))
    print

收益率

['Rs.11,800.00']
['Rs.13,299.00', 'Rs.11,800.00']
['Rs.13,299.00', 'Rs.11,800.00']

[]
['Rs.7,000.00']
['Rs.7,000.00']

另一种获取你想要的信息的方法是

"//*[@class='productSpecialPrice' or @class='proDetPrice']//text()"