使用布尔值与Python lxml执行不同的XPath表达式

Question

我试图使用python脚本和lxml从网站上获取天气数据。风速数据将被拉出并附加到一个列表中，以便以后进行操作。我可以很好地获得我需要的信息，当它被格式化时：

<div class = "day-fcst">
  <div class = "wind">
    <div class = "gust">
      "Gusts to 20-30mph"
    </div>
  </div>
</div>

<div class = "gust">
  <span class = "nowind">
    "Gusts less than 20mph"
  </span
</div>

我当前的代码使用Python检查span类是否等同于“nowind”，然后执行if和else语句，但只执行else语句。我当前的代码如下所示：

from lxml import html
import requests

wind = []

source=requests.get('website')
tree = html.fromstring(source.content)

if tree.xpath('//div[@class = "day-fcst"]/div[@class = "wind"]/div[@class = "gust"]/span/@class') == 'nowind':
  wind.append(tree.xpath('//div[@class = "day-fcst"]/div[@class = "wind"]/div[@class = "gust"]/span/text()'))
else:
  wind.append(tree.xpath('//div[@class = "day-fcst"]/div[@class = "wind"]/div[@class = "gust"]/text()'))

print wind

我想用一个XPath表达式来解决这个问题，该表达式将产生一个布尔值，而不是我当前的解决方案。如有任何帮助，不胜感激。我对使用XPath还是新手，因此对使用它的任何功能都不熟悉。

Answer 1

相关问题

Answer 2

对于这两种情况，可以使用相同的xpath表达式。只需使用//div[@class=“day-fcst”]/div[@class=“wind”]/div[@class=“gust”]//text()

或者，您可以获取

元素，并使用 text_content()方法获取文本内容。

In [1]: from lxml import html

In [2]: first_html = '<div class = "day-fcst"><div class = "wind"><div class = "gust">"Gusts to 20-30mph"</div></div></div>'

In [3]: second_html = '<div class = "day-fcst"><div class = "wind"><div class = "gust"><span class = "nowind">"Gusts to 20-30mph"</span></div></div></div>'

In [4]: f = html.fromstring(first_html)

In [5]: s = html.fromstring(second_html)

In [6]: f.xpath('//div[@class = "day-fcst"]/div[@class = "wind"]/div[@class = "gust"]')[0].text_content()
Out[6]: '"Gusts to 20-30mph"'

In [7]: s.xpath('//div[@class = "day-fcst"]/div[@class = "wind"]/div[@class = "gust"]')[0].text_content()
Out[7]: '"Gusts to 20-30mph"'

In [8]: print(f.xpath('//div[@class = "day-fcst"]/div[@class = "wind"]/div[@class = "gust"]//text()'))
['"Gusts to 20-30mph"']

In [9]: print(s.xpath('//div[@class = "day-fcst"]/div[@class = "wind"]/div[@class = "gust"]//text()'))
['"Gusts to 20-30mph"']