Question

I have several information entries that I want to separate with a comma. However, each entry could be empty, and if the first-appearing entry is empty, then comma should not appear. For example:

if we have four XSLT parameters: name, phone number, address, occupation

and we have

• Name: John
• Phone number: 111-111-1111
• Address: Imaginary street
• Occupation: Baker

Then final string should be:

John, 111-111-1111, Imaginary street, Baker

if the name and phone number parameters were empty or null, then final string should be:

Imaginary street, Baker

if only phone number null or empty, then final string should be:

John, Imaginary street, Baker

In a language like C#, I would write the code like this:

foreach (EntryObject entry in entryList)
{
    if (firstEntry == true && entry.Type != EntryType.Age && entry.Type != EntryType.Sex)
    {
        finalString += entry.ValueString;
        firstEntry = false;
    }
    else if (firstEntry == false && entry.Type != EntryType.Age && entry.Type != EntryType.Sex)
    { 
        finalString += ", " + entry.ValueString;
    }
}
return finalString;

However, I heard that variables in XSLT are immutable. How should I approach this problem in XSLT?

Edit:
The xml entry would look something like this:

<AddressBook>
    <PersonalInfo>
        <Age>33</Age>
        <Sex>Male</Sex>
        <Name>John</Name>
        <PhoneNumber></PhoneNumber>
        <Address>Imaginary Street</Address>
        <Occupation>Baker</Occupation>
    </PersonalInfo>
</AddressBook>

Note that certain entries could be empty, and I will only use name, phonenumber, address and occupation. Age and Sex should be ignored.

Answer 1

Use an XPath condition that matches only the non-empy elements (string-length(.)>0 or simply string(.)), and then use the position() function to check if an element is the first or not. Input XML:

<root>
  <item>
    <name>John</name>
    <phoneNumber>111-111-1111</phoneNumber>
    <address>Imaginary street</address>
    <occupation>Baker</occupation>
  </item>
  <item>
    <name>Jane</name>
    <address>Another street</address>
    <occupation>Decorator</occupation>
  </item>
  <item>
    <address>Unknown</address>
  </item>
</root>

XSLT:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

  <xsl:template match="item">
    <textItem>
      <xsl:for-each select="*[string(.)]">
        <xsl:if test="position()>1">
          <xsl:text>,</xsl:text>
        </xsl:if>
        <xsl:value-of select="."/>
      </xsl:for-each>
    </textItem>
  </xsl:template>

  <xsl:template match="text()">
  </xsl:template>

  <xsl:template match="root">
    <root>
      <xsl:apply-templates/>
    </root>
  </xsl:template>

</xsl:stylesheet>

where the first template is the one actually doing the work, <xsl:template match="text()"> removes the text contained in unmatched elements (by default XSLT processor would copy such text to the output) and <xsl:template match="root"> generates the root element of the output document.

Result:

<root>
  <textItem>John,111-111-1111,Imaginary street,Baker</textItem>
  <textItem>Jane,Another street,Decorator</textItem>
  <textItem>Unknown</textItem>
</root>

If you are interested in only some of the fields you just select them using the union operator (|) – e.g. if you want only phone, address and occupation in the example above modify the XSLT to be:

  <xsl:template match="item">
    <textItem>
      <xsl:for-each select="(phoneNumber|address|occupation)[string(.)]">
        <xsl:if test="position()>1">
          <xsl:text>,</xsl:text>
        </xsl:if>
        <xsl:value-of select="."/>
      </xsl:for-each>
    </textItem>
  </xsl:template>

  <xsl:template match="text()">
  </xsl:template>

  <xsl:template match="root">
    <root>
      <xsl:apply-templates/>
    </root>
  </xsl:template>

</xsl:stylesheet>