How do I check if XML value is nil in XSLT

In an XML document I have some address data..

<zip>08001</zip>
<zipPlus xsi:nil="true" />

and

<zip>08002</zi开发者_如何学编程p>
<zipPlus>4512</zipPlus>

On only want to bother displaying the zip plus value if there is a value to use. (for the purposes of this example, I don't care if its a correct zip plus format or not)

Trying to use the following snippet in an XSLT never seems to work right, and I think it has to do with how I am checking for the xsl:nil value

<EmployerZipCode>
      <xsl:value-of select="zip"/>
      <xsl:if test="zipPlus != @xsl:nil">
        <xsl:value-of select="'-'"/>
        <xsl:value-of select="zipPlus"/>
      </xsl:if>
      <xsl:value-of select="$sepChar"/> <!--this is a comma -->
</EmployerZipCode>

The results I get are always

08001,
08002,

not

08001,
08002-4512,

What is the proper way to check for nil-led elements in XSLT? Are there any other ways to get around this problem and get the result I want?

---

<xsl:if test="not(zipPlus/@xsi:nil='true')">

---

In XSLT 2.0, for reasons I have never fully understood, there is a custom function

test="not(nilled(zipPlus))"

---

After some more testing, none of answers given that involve checking the nil attribute work reliably.

I had to resort to using string-length() to get the result I needed.

<EmployerZipCode>
  <xsl:value-of select="zip"/>
  <xsl:if test="string-length(zipPlus) &gt; 0">
    <xsl:value-of select="'-'"/>
    <xsl:value-of select="zipPlus"/>
  </xsl:if>
  <xsl:value-of select="$sepChar"/>
</EmployerZipCode>

---

It's very strange that you didn't get it to work. Perhaps it might be you are missing namespace declaration or the prefix change xsi to xsl is an unseen typo in your transform. Check better. Here my test:

XSLT 1.0 with Saxon 6.5

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:xsi="test">
    <xsl:output method="text" indent="yes"/>

    <xsl:template match="EmployerZipCode">
        <EmployerZipCode>
            <xsl:value-of select="zip"/>
            <xsl:if test="not(zipPlus/@xsi:nil)">
                <xsl:value-of select="'-'"/>
                <xsl:value-of select="zipPlus"/>
            </xsl:if>
            <xsl:value-of select="','"/> <!--this is a comma -->
        </EmployerZipCode>
    </xsl:template>
</xsl:stylesheet>

Given the input:

<?xml version="1.0" encoding="utf-8"?>
<test xmlns:xsi="test">
    <EmployerZipCode>
        <zip>08001</zip>
        <zipPlus xsi:nil="true" />
    </EmployerZipCode>
    <EmployerZipCode>
        <zip>08002</zip>
        <zipPlus>4512</zipPlus>
    </EmployerZipCode>
</test>

Produces:

08001,
08002-4512,

---

It works for me

Source XML :

            <zipPlus xsi:nil="true"/>
                      or
            <zipPlus>123456</zipPlus>

XSLT :

            <xsl:if test="not(zipPlus/@xsl:nil='true')">
                <xsl:value-of select="zipPlus"/>
            </xsl:if>

Result XML

            <zipPlus/>
            or
            <zipPlus>123456</zipPlus>