Question

I am writing xsl stylesheet to extract information from iTunes Music Library. xml file.

I want to store track information of playlists in an array and later iterate over them to get more information. I am confused how to store values in an array in xslt?

My attempt is here:

    <?xml version="1.0" encoding="ISO-8859-1"?>
    <xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:output method="text" /> 
    <xsl:template match="/"> 

    <xsl:variable name="tracks"
           select="plist/dict/array/dict[integer[preceding-sibling::key[1]='Playlist ID']=6711]/array/dict/integer[preceding-sibling::key[1]='Track ID']" />

    <!-- I want to iterate over that array outside for-each loop and gather more information, The below code is not working.-->

   <xsl:for-each select="$tracks">
  <xsl:value-of select="." />
  <xsl:value-of select="plist/dict/dict/dict[integer[preceding-sibling::key[1]='Track ID']="."]/integer[preceding-sibling::key[1]='Track ID']" />
  <xsl:value-of select="plist/dict/dict/dict[integer[preceding-sibling::key[1]='Track ID']="."]/string[preceding-sibling::key[1]='Name']" />
  <xsl:value-of select="plist/dict/dict/dict[integer[preceding-sibling::key[1]='Track ID']="."]/string[preceding-sibling::key[1]='Total Time']" />
  <xsl:value-of select="plist/dict/dict/dict[integer[preceding-sibling::key[1]='Track ID']="."]/string[preceding-sibling::key[1]='Location']" />
  <xsl:text>&#xa;</xsl:text>
</xsl:for-each>


    </xsl:template>
    </xsl:stylesheet>

A typical Track Ids which are populated in array variable “tracks”, are represented in below manner in itunes list. I want to list Name, Location, time infor for each Track Ids stored in the array. Something wrong with my conditions.

<plist>
  <dict>
    <dict>
      <dict>
        <key>Track ID</key>
        <integer>1633</integer>
        <key>Name</key>
        <string>Right here</string>
        <key>Kind</key>
        <string>MPEG audio file</string>
        <key>Total Time</key>
        <integer>358870</integer>
        <key>Location</key>
        <string>/Users/rakesh/Music/iTunes/iTunes%20Media/Music/track1633.mp3</string>
      </dict>
      <dict> 
        <!-- Next Track info -->
      </dict>
    </dict>
  </dict>
</plist>

Here I am stuck. Can any XSLT experts here to help me out?

Answer 1

You could just create a variable and populate its results with an XPath expression all in one go rather than interate through to build it.

<xsl:variable name="tracks"
  select="plist/dict/array/dict[integer[preceding-sibling::key[1]='Playlist ID']=6711]/array/dict/integer[preceding-sibling::key[1]='Track ID']" />

Alternatively you could use xsl:keys at the begining of your document, I’m assuming that the path to the track information is /plist/dict/array/dict with the first dict key being Tracks

<xsl:key 
        name="playlists"
        match="plist/dict/array/dict/array/dict/integer[preceding-sibling::key[1]='Track ID']"
        use="../../../integer[preceding-sibling::key[1]='Playlist ID']"
/>
<xsl:key 
       name="tracks" 
       match="/plist/dict/array[preceding-sibling::key[1]='Tracks']/dict"
       use="integer[preceding-sibling::key[1]='Track ID']"
/>

This allows you to do key('playlists','4555') to return all the trackids associated with playlist id 4555 and also key('tracks','1234') to get the dict object associated with track id 1234

You can then combine the two together to do

<xsl:variable "mytracks" select="key('tracks',key('playlists','6711'))" />

That will set $mytracks equal to the array of dict objects for the tracks in playlist 6711. It aslo has the benefits of the speed enhancement granted by xsl:key

EDIT UPDATE—-

I’m guessing you are trying to make a CSV from this so this code should do that

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:msxsl="urn:schemas-microsoft-com:xslt" exclude-result-prefixes="msxsl">
  <xsl:output method="text" />
  <xsl:key
    name="playlists"
    match="plist/dict/array/dict/array/dict/integer[preceding-sibling::key[1]='Track ID']"
    use="../../../integer[preceding-sibling::key[1]='Playlist ID']"
  />
  <xsl:key
    name="tracks"
    match="/plist/dict/dict/dict"
    use="integer[preceding-sibling::key[1]='Track ID']"
  />

  <xsl:template match="/">
    <xsl:variable name="myplaylist" select="'6711'"/>
    <xsl:for-each select="key('tracks',key('playlists',$myplaylist))">
      <xsl:value-of select="integer[preceding-sibling::key[1]='Track ID']"/>
      <xsl:text>,</xsl:text>
      <xsl:value-of select="string[preceding-sibling::key[1]='Name']"/>
      <xsl:text>,</xsl:text>
      <xsl:value-of select="integer[preceding-sibling::key[1]='Total Time']"/>
      <xsl:text>,</xsl:text>
      <xsl:value-of select="string[preceding-sibling::key[1]='Location']"/>
      <xsl:text>&#xa;</xsl:text>
    </xsl:for-each>
  </xsl:template>
</xsl:stylesheet>

to match a different playlist id just change the value of myplaylist

–EDIT Version without xsl:key ,again just alter the value of the myplaylist variable

–EDIT Now mofified to original sort order of playlist
–EDIT Attempt to work around Qt Limitations

  <?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:msxsl="urn:schemas-microsoft-com:xslt" exclude-result-prefixes="msxsl">
  <xsl:output method="text" />

  <xsl:template match="/">
    <xsl:variable name="myplaylist" select="'4053'"/>
    <xsl:variable name="playlist_tracks" select="/plist/dict/array/dict[integer[preceding-sibling::key[1]='Playlist ID']=$myplaylist]/array/dict/integer[preceding-sibling::key[1]='Track ID']" />

    <xsl:for-each select="$playlist_tracks">
      <xsl:variable select="." name="current" />
      <xsl:for-each select ="/plist/dict/dict/dict[integer[preceding-sibling::key[1]='Track ID']=$current]" >
        <xsl:value-of select="integer[preceding-sibling::key[1]='Track ID']"/>
        <xsl:text>,</xsl:text>
        <xsl:value-of select="string[preceding-sibling::key[1]='Name']"/>
        <xsl:text>,</xsl:text>
        <xsl:value-of select="integer[preceding-sibling::key[1]='Total Time']"/>
        <xsl:text>,</xsl:text>
        <xsl:value-of select="string[preceding-sibling::key[1]='Location']"/>
        <xsl:text>&#xa;</xsl:text>
      </xsl:for-each>
    </xsl:for-each>
  </xsl:template>
</xsl:stylesheet>