python - 不确定如何 XPath 到特定的网站元素

Question

我目前正在尝试使用 Scrapy 浏览 Elite Dangerous subreddit 并收集帖子标题、网址和投票数。我前两个做得很好，但不确定如何编写 XPath 表达式来访问投票。

selector.xpath('//div[@class="score unvoted"]').extract()有效，但它返回当前页面上所有帖子的投票计数(而不是每个单独的帖子)。 response.css('div.score.unvoted').extract()适用于每个单独的帖子，但返回 [u'<div class="score unvoted">1</div>'] ，而不仅仅是 1。(我也很想知道如何使用 XPath 做到这一点!:))

代码如下:

class redditSpider(CrawlSpider):  # http://doc.scrapy.org/en/1.0/topics/spiders.html#scrapy.spiders.CrawlSpider
    name = "reddits"
    allowed_domains = ["reddit.com"]
    start_urls = [
    "https://www.reddit.com/r/elitedangerous",
    ]

    rules = [
        Rule(LinkExtractor(
            allow=['/r/EliteDangerous/\?count=\d*&after=\w*']),  # Looks for next page with RE
        callback='parse_item',  # What do I do with this? --- pass to self.parse_item
        follow=True),  # Tells spider to continue after callback
    ]

    def parse_item(self, response):
        selector_list = response.css('div.thing') # Each individual little "box" with content

        for selector in selector_list:
            item = RedditItem()
            item['title'] = selector.xpath('div/p/a/text()').extract()
            item['url'] = selector.xpath('a/@href').extract()
            # item['votes'] = selector.xpath('//div[@class="score unvoted"]')
            item['votes'] = selector.css('div.score.unvoted').extract()
            yield item

Answer 1

您走在正确的道路上。第一种方法只需要两件事:

• 开头加一个点，使其成为 context-specific
• text() 位于末尾

修复版本:

selector.xpath('.//div[@class="score unvoted"]/text()').extract()

而且，仅供引用，您也可以使用 ::text pseudo-element 来使第二个选项起作用。 :

response.css('div.score.unvoted::text').extract()