如何使用Scrapy找出具有相同名称的类数？

Question

如何使用Scrapy找出班级名称中带有单词“ on”的班级数量？

<div class="listing item-rating" style="display: block;">
  <img src="/Content/images/spacer.gif" class="star-left on">
  <img src="/Content/images/spacer.gif" class="star-right on">  
  <img src="/Content/images/spacer.gif" class="star-left on">
  <img src="/Content/images/spacer.gif" class="star-right of">  
  <img src="/Content/images/spacer.gif" class="star-left of">
  <img src="/Content/images/spacer.gif" class="star-left of">
</div>

Answer 1

• response.xpath('//*[has-class("on")]')为您提供选择器（所有具有'on'的类）
• [len(response.xpath('//*[has-class("on")]'))为您提供长度-在这种情况下，是课程数量