Xpath表达式根据子节点的存在选择节点? [英] Xpath Expression to select nodes based on presence of child node?

问题描述

我正在尝试使用 Xpath 查找具有给定 CSS 类 (.product) 的所有

.

<a href="#product/1966740"><img class="cover_image" src="https://foobar.JPG" alt="foobar" title="foobar"><h3>foobar</h3></a><div class="price">$66.00</div><div class="rrp">$219.11</div>

所以找到这些的 Xpath 相对简单:

//div[@class="product"]

但是，我只想找到那些没有售罄的产品.售罄的产品如下所示:

<img class="availability" src="https://sold_out_tag.png" alt="sold out"><a href="#product/1963553"><img class="cover_image" src="foobar.jpg" alt="foobar" title="foobar"><h3>FooBar<h3></a><div class="price">$40.00</div><div class="rrp">$129.33</div>

我想我可以使用 not()，并检查

不包含 并将 alt 属性设置为售罄".

但是，以下内容无效:

//div[@class="product" and not([img[@alt="sold out"]])]

关于如何让它工作的任何想法?

干杯，维克多

解决方案

您就快到了.您不需要 [] 在 img 子路径周围:

//div[@class="product" and not(img[@alt = "sold out"])]

另一种写基本相同的东西的方法是:

//div[@class="product" and not(img/@alt = "sold out")]

最后，由于 class 属性可以包含多个类，通常最好使用 contains() 来检查类:

//div[contains(concat(' ', @class, ' '), " product ") 而不是(img/@alt = "sold out")]

I'm trying to use Xpath to find all <div>s with a given CSS class (.product).

<div class="product">
    <a href="#product/1966740"><img class="cover_image" src="https://foobar.JPG" alt="foobar" title="foobar">
    <h3>foobar</h3></a>
    <div class="price">$66.00</div>
    <div class="rrp">$219.11</div>
</div>

So the Xpath to find those is relatively simple:

//div[@class="product"]

However, I only want to find those products that aren't sold out. Sold out products look like this:

<div class="product">
    <img class="availability" src="https://sold_out_tag.png" alt="sold out">
    <a href="#product/1963553"><img class="cover_image" src="foobar.jpg" alt="foobar" title="foobar">
    <h3>FooBar<h3></a>
    <div class="price">$40.00</div>
    <div class="rrp">$129.33</div>
</div>

I was thinking I can use not(), and check for <div>s that do not contain an <img> with the alt attribute set to "sold out".

However, the following isn't valid:

//div[@class="product" and not([img[@alt="sold out"]])]

Any thoughts on how to get this working?

Cheers, Victor

解决方案

You were almost there. You don't need []s around the img sub-path:

//div[@class="product" and not(img[@alt = "sold out"])]

Another way to write essentially the same thing is:

//div[@class="product" and not(img/@alt = "sold out")]

Lastly, since class attributes can contain more than one class, it's often better to use contains() to check for classes:

//div[contains(concat(' ', @class, ' '), " product ") and not(img/@alt = "sold out")]

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