XSL:Number count not working as expected — Issue w

问题:

Here's the XML

<row>
    <cell>blah blah</cell>

    <check>
        <option/>
        <option/>
        <option/>
        <option/>
        <option/>
        <option/>
    </check>
</row>

Here is the XSL

<xsl:template match="row">
    <xsl:variable name="inputLevel">
        <xsl:number count="option" level="any" from="."/>
    </xsl:variable>

    <xsl:value-of select="$inputLevel"/>
</xsl:template>

All I get is "0". http://www.w3schools.com/XPath/xpath_syntax.asp says "." means the current node. Shouldn't it be returning "6"?

Edit1: I wanted to look for option tags at ANY level, not just check. Should have explained but the option tags could exist at any level below

回答1:

If you want to count descendant options you shouldn't use xsl:number but:

<xsl:variable name="inputLevel" select="count(.//option)"> 

回答2:

I think the problem is that the xpath expression option won't match anything at the row element - try this instead:

<xsl:number count="check/option" level="any" from="." />

To look for option elements at any level use the following syntax:

<xsl:number count="//option" level="any" from="." />

I don't think the from attribute is reqired, and the level attribute probably isn't doing what you think it is (I'm also not sure what it does...)

回答3:

From the XSLT 1.0 W3C specification:

"If no value attribute is specified, then the xsl:number element inserts a number based on the position of the current node in the source tree. The following attributes control how the current node is to be numbered:

The levelattribute specifies what levels of the source tree should be considered; it has the values single, multiple or any. The default is single.

The count attribute is a pattern that specifies what nodes should be counted at those levels. If count attribute is not specified, then it defaults to the pattern that matches any node with the same node type as the current node and, if the current node has an expanded-name, with the same expanded-name as the current node

When level="any", it constructs a list of length one containing the number of nodes that match the count pattern and belong to the set containing the current node and all nodes at any level of the document that are before the current node in document order, excluding any namespace and attribute nodes (in other words the union of the members of the preceding and ancestor-or-self axes). If the from attribute is specified, then only nodes after the first node before the current node that match the from pattern are considered. ".

From this text it is clear that only nodes that are ancestors or are preceding the current node are counted.

In this question, the current node is the top element node row and it has 0 ancestor and 0 preceding element nodes.

Therefore, the returned result is correct!

Solution:

Use:

count(descendant::option)

The result of evaluating this expression is the count of all option elements in the document, that are descendents of the current node (the row element).