如何跳出 XSLT 中的 xsl:for-each 循环? [英] How to break out of xsl:for-each loop in XSLT?

问题描述

我知道 XSLT 不允许直接跳出 xsl:for-each 循环，但必须有一种简单的方法来添加更多条件来实现它.我在相同的上下文中看到了很多在线内容，但无法进一步进行.

I understand that XSLT doesn't allow one to directly break out of a xsl:for-each loop, but there must be an easy way to add more conditions to achieve it. I've seen much online on the same context but unable to proceed further.

我想遍历一组 XML 标签，然后在查找一个 XML 标签中的值并在另一个 xsl:template 中使用该值时退出迭代.例如，

I want to iterate through a set of XML tags and come out of the iteration on finding a value in one XML tag and use that value in another xsl:template. For example,

<xsl:template name="categoryCheckTemplate">
 <xsl:for-each select="TEST/ABC/DEF/GHI/Row">
    <xsl:variable name="category">
        <xsl:choose>
            <xsl:when test="JKL/Category">
                <xsl:value-of select="JKL/Category"/>                           
            </xsl:when>
            <xsl:when test="MNO/Category">
                <xsl:value-of select="MNO/Category"/>                           
            </xsl:when>
        </xsl:choose>
    </xsl:variable>
    <xsl:choose>
        <xsl:when test="(contains($category,'123'))">
            <xsl:value-of select="'true'"/>    
        </xsl:when>
        <xsl:otherwise>
            <xsl:value-of select="'false'"/>
        </xsl:otherwise>
    </xsl:choose>
 </xsl:for-each>
</xsl:template>

我想在另一个模板中使用这个模板的 'true' 值，但不想一直迭代它.任何时候都是真的，我需要从迭代中出来.

I want to use the 'true' value of this template in another template but don't want to iterate it all the way. Anytime it is true, I need to come out of the iteration.

XML 输入

<xml>
    <TEST>
        <ABC>
            <DEF>
                <GHI>
                    <Row>
                        <JKL>
                            <Category>123</Category>
                        </JKL>
                    </Row>
                    <Row>
                        <JKL>
                            <Category>456</Category>
                        </JKL>
                    </Row>
                    <Row>
                        <JKL>
                            <Category>789</Category>
                        </JKL>
                    </Row>
                    <Row>
                        <JKL>
                            <Category>012</Category>
                        </JKL>
                    </Row>
                </GHI>
            </DEF>
        </ABC>
    </TEST>
</xml>

期望输出

<item>
    <cat>123</cat>
</item>

有人可以帮忙解决这个 XSLT 1.0 吗?

Can anyone help on this XSLT 1.0?

推荐答案

你想得太程序化了.你不需要打破；你甚至不需要循环.

You're thinking too procedurally. You don't need to break; you don't even need to loop.

您的整个过程可以而且应该简化为单个 XPath 表达式:

Your entire procedure can and should be reduced to a single XPath expression:

string(contains(TEST/ABC/DEF/GHI/Row/*[self::JKL or self::MNO]/Category, '123'))

就是这样.没有循环.没有休息.只需针对输入 XML 和可选的字符串转换进行测试(在您的实际上下文中可能需要也可能不需要).

That's it. No loop. No break. Just tests against the input XML and an optional conversion to string (which may or may not be necessary in your actual context).

这个 XSLT，

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
  <xsl:output method="xml" indent="yes"/>
  <xsl:template match="/">
    <item>
      <xsl:if test="/xml/TEST/ABC/DEF/GHI/Row/
                    *[self::JKL or self::MNO]/Category = 123">
        <cat>123</cat>
      </xsl:if>
    </item>
  </xsl:template>
</xsl:stylesheet>

将产生请求的输出 XML，

will produce the requested output XML,

<item>
   <cat>123</cat>
</item>

如果原始程序指定的条件为真¹，或此输出 XML，

if the original procedurally specified condition is true¹, or this output XML,

<item/>

否则.

_{¹ 我冒昧地也从字符串包含测试切换到字符串值相等测试，这更有可能是这里想要的(否则1234"等人也会满足测试).}

_{¹ I took the liberty of also switching from a string contains test to a string value equality test, which is more likely what's desired here (else "1234" et al would also satisfy the test).}

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