creating arrays in xslt

问题:

can array's be created and used in xslt? If so are there suitable examples online to study? If not is there a way to store values in a way that mimics an array?

回答1:

With XSLT 2.0 you can model any data type you want to.

As example:

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:output method="text" omit-xml-declaration="yes"/>
    <xsl:variable name="array" as="element()*">
        <Item>A</Item>
        <Item>B</Item>
        <Item>C</Item>
    </xsl:variable>
    <xsl:template match="/">
        <xsl:value-of select="$array[2]"/>
    </xsl:template>
</xsl:stylesheet>

With any input, output:

B

In XSLT 1.0 there is not Temporaly Result Tree data type. There is a Result Tree Fragment data type that does not allow node-set operator. So, the only way to go is with extensions functions: in this case node-set() from EXSLT (MSXSL has a built-in node-set() extension, also).

So, in XSLT 1.0 without extensions you can have only inline data model, or by params or by external document. As example:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:output method="text" omit-xml-declaration="yes"/>
    <xsl:variable name="inline-array">
        <Item>A</Item>
        <Item>B</Item>
        <Item>C</Item>
    </xsl:variable>
    <xsl:param name="array" select="document('')/*/xsl:variable[@name='inline-array']/*"/>
    <xsl:template match="/">
        <xsl:value-of select="$array[2]"/>
    </xsl:template>
</xsl:stylesheet>

Result, with any input:

B

Only if you want to, I can provide you a XSLT 1.0 plus extensions example (It's not standar...)

回答2:

The XPath 2.0 sequence (available in XSLT 2+) is the closest thing to an array:

(1 to 10)[3]

evaluates to 3

('a', 'b', 'a', 'c')[3]

evaluates to 'a'

The items of a sequence can be of any conceivable type allowed in XPath, with the exception of sequence itself -- nested sequences are not allowed.

Do note: Sequences are not the same as arrays:

1. Sequences are immutable. Any updating operation on a sequence (appending or prepending an item, inserting an item or removing an item) produces a new sequence.

2. The access time to the n-th item is not guaranteed to be O(1) as this is for arrays, and may be O(n).

回答3:

No, not as such. The closest concept is node-sets, which are collections of nodes. Whenever the result of a select is a number of nodes, you get a node-set. These can be accessed with a index notation (starting with 1), so the first element of the node-set can be accessed with notation such as selectedNodes[1].

回答4:

With XSLT 2.0 you can simply use

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:xs="http://www.w3.org/2001/XMLSchema"
    exclude-result-prefixes="xs"
    version="2.0">
    <xsl:output omit-xml-declaration="yes"/>
    <xsl:template match="/">
    <xsl:variable name="array" select="('A','B','C')"/> 
        <xsl:value-of select="$array[2]"/>
    </xsl:template>
</xsl:stylesheet>