XPath 1.0:查找指定节点之前的节点数 [英] XPath 1.0: Finding count of nodes before a specified node

问题描述

我熟悉在XSLT中使用前置轴来确定确定给定当前上下文的前面的元素.但是，对于给定存储在变量中的节点，我看不到有办法做到这一点.例如:

I am familiar with using preceding axes in XSLT for finding determining the number of preceding elements given the current context. However, I don't see a way to do the same given a node that I've stored in a variable. For example:

<xsl:variable name="matchedBook" select="book[text()='The Hobbit']"/>
<xsl:variable name="precedingBookCount" select="count(???)"/>

鉴于以下XML，precedingBookCount应该等于3.

Given the following XML, precedingBookCount should equal 3.

<available>
    <book>Lord of the Rings</book>
    <book>The Hunger Games</book>
</available>
<purchased>
    <book>Ready Player One</book>
    <book>The Hobbit</book>
    <book>Lord of the Flies</book>
</purchased>

我在XPath 2.0中看到有一个 NodeComp运算符我可以使用的<<，但是XPath 1.0中似乎没有.

I see in XPath 2.0 that there is a NodeComp operator << that I could use, but this does not appear to be present in XPath 1.0.

那我该如何在XPath 1.0中做到这一点?

How can I go about doing this in XPath 1.0 then?

推荐答案

<xsl:variable name="precedingBookCount" select="count($matchedBook/preceding-sibling::book | $matchedBook/preceding::book)"/>应该可以.

实际上，做<xsl:variable name="precedingBookCount" select="count($matchedBook/preceding::book)"/>就足够了.

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