xml 如何在 XSLT 中更改或重新分配变量？
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How to change or reassign a variable in XSLT?
提问by Manuel Franqueira
How can I reassign a value to a variable previously assigned? I need it to works like this:
如何将值重新分配给先前分配的变量？我需要它像这样工作：
<xsl:variable name="variable2" select="'N'" />
....
<xsl:when test="@tip = '2' and $variable2 != 'Y'">
<xsl:variable name="variable2" select="'Y'" />
</xsl:when>
采纳答案by kjhughes
Variables in XSLT may only be assigned a value once. This is done by design. See Why Functional languages?for an appreciation of the motivation in general.
XSLT 中的变量只能赋值一次。这是由设计完成的。请参阅为什么使用函数式语言？以了解总体动机。
Rather than reassign a variable, write conditionals against the input document directly, or call a function (or named template) recursively with varying local parameters.
不是重新分配变量，而是直接针对输入文档编写条件，或者使用不同的局部参数递归调用函数（或命名模板）。
Anything you need to do can be done with an approach that does not require reassignment of variables. To receive a more specific answer, provide a more specific question.
您需要做的任何事情都可以通过不需要重新分配变量的方法来完成。要获得更具体的答案，请提供更具体的问题。
See also:
也可以看看：
回答by Gary Sheppard
Just use multiple variables. Here's your example made to work...
只需使用多个变量。这是您的示例工作...
<xsl:variable name="variable1" select="'N'" />
....
<xsl:variable name="variable2">
<xsl:choose>
<xsl:when test="@tip = '2' and $variable1 != 'Y'">
<xsl:value-of select="'Y'" />
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$variable1" />
</xsl:otherwise>
</xsl:choose>
</xsl:variable>
回答by MiMo
You cannot - 'variables' in XSLT are actually more like constants in other languages, they cannot change value.
你不能 - XSLT 中的“变量”实际上更像是其他语言中的常量，它们不能改变值。
回答by Wolfgang Grinfeld
Reassignable variables can be declared using an accumulator, available from XSLT version 3.0. :
可使用累加器声明可重新分配的变量，可从 XSLT 3.0 版获得。：
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:xs="http://www.w3.org/2001/XMLSchema" exclude-result-prefixes="xs" version="3.0" >
<xsl:mode use-accumulators="variable2" streamable="no"/>
<xsl:output omit-xml-declaration="no" indent="yes"/>
<xsl:accumulator name="variable2" initial-value="'N'">
<xsl:accumulator-rule match="Inpayment" select="if ($value = 'N' and @tip = '2') then 'Y' else 'N' "/>
</xsl:accumulator>
<xsl:template match="node()|@*">
<xsl:copy>
<xsl:apply-templates select="node()|@*"/>
</xsl:copy>
</xsl:template>
<xsl:template match="Inpayment">
<xsl:copy>
<xsl:apply-templates select="@*"/>
<xsl:value-of select="accumulator-before('variable2')"/>
<xsl:apply-templates select="node()"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
回答by cmf41013
I just almost believe the viewpoint in other replies before I test. It can really run well like that. xslt processor is saxon-he 9.8.0.12
在我测试之前，我几乎相信其他回复中的观点。它真的可以像那样运行良好。xslt 处理器是 saxon-he 9.8.0.12
my code ：
我的代码：
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:map="http://www.w3.org/2005/xpath-functions/map"
exclude-result-prefixes="xs map"
version="2.0">
<xsl:template match="/">
<xsl:variable name="i1" select="123" as="xs:integer"/>
<xsl:variable name="s1" select="'abcd'" as="xs:string"/>
<xsl:variable name="d1" select="234.5" as="xs:float"/>
<!-- we test that variable v1 can be assignment multi times and it is ok. -->
<xsl:variable name="v1" select="$i1"/>
v1 is: <xsl:value-of select="$v1"/>
<xsl:variable name="v1" select="$s1"/>
v1 is: <xsl:value-of select="$v1"/>
<xsl:variable name="v1" select="$d1"/>
v1 is: <xsl:value-of select="$v1"/>
<xsl:variable name="map1" select="map{'haha':119, 'good':110}"/>
<xsl:variable name="map2" select="map:put($map1, 'go', 122)"/>
<xsl:variable name="map1" select="map:put($map2, 'hello', 999)"/>
map1(haha) is <xsl:sequence select="$map1?haha"/>
map1(hello) is <xsl:sequence select="$map1?hello"/>
</xsl:template>
</xsl:stylesheet>
the result screenshort of the running
as your question, you can do like that:
作为你的问题，你可以这样做：
<xsl:variable name="variable2" select="'N'" />
<xsl:variable name="variable2" select="hello:func1()" />
<xsl:function name="hello:func1" as="xl:string">
.....
<xsl:when test="@tip = '2' and $variable2 != 'Y'">
<xsl:value-of select="'Y'" />
</xsl:when>
</xsl:function>
