Sorting XML file by element

Question

I want to sort a xml file by elements in the same level alphabetically. That means, sorting the elements on the first level, then inside every element their subelement and so on recursively. It must be multilevel, not only one level (that is solved in other question). For example (please ignore the content and the meaning):

<example>
    <note>
        <to>Tove</to>
        <from>Jani</from>
        <heading>Reminder</heading>
            <headb>head</head3>
            <heada>head</head3>
        <body>Don't forget me this weekend!</body>
    </note>
    <next>
        <c>blabla</c>
        <a>blabla</a>
    </next>
</example>

To:

<example>
    <next>
        <a>blabla</a>
        <c>blabla</c>
    </next>
    <note>
        <body>Don't forget me this weekend!</body>
        <from>Jani</from>
        <heading>Reminder</heading>
            <heada>head</head3>
            <headb>head</head3>
        <to>Tove</to>
    </note>
</example>

The xml can contain thousands of lines and many levels of elements

possible duplicate of [sort XML tags into alphabetical order](http://stackoverflow.com/questions/9161934/sort-xml-tags-into-alphabetical-order) — Jen R, Jun 18 '15 at 19:17
That did not work for my example, as there is only one level in that one. I will ask in the other post my problem. — Weslor, Jun 18 '15 at 20:00

Daniel Haley · Accepted Answer · 2015-06-18T20:37:52.840

You should be able to use an identity transform and add the xsl:sort to sort on either name() or local-name().

Example...

XML Input (Well formed and slightly more complicated than the original.)

<example>
    <note>
        <to>Tove</to>
        <from>Jani</from>
        <heading>Reminder</heading>
        <headb>head</headb>
        <heada>head</heada>
        <body>Don't forget me this weekend!</body>
    </note>
    <next>
        <c>blabla</c>
        <a>blabla</a>
    </next>
    <djh>
        <!-- comment -->
        <foo attr="test">
            <bar>
                <baz>text</baz>
                <foo><!--comment--></foo>
            </bar>
            <baz attr="test">
                <foo/>
                <bar/>
            </baz>
        </foo>
        <?PI?>
        <baz>
            <bar>
                <foo/>
                <baz/>
            </bar>
            <foo>
                <bar/>
                <baz/>
            </foo>
        </baz>
    </djh>
</example>

XSLT 1.0

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:output indent="yes"/>
    <xsl:strip-space elements="*"/>

    <xsl:template match="@*|node()">
        <xsl:copy>
            <xsl:apply-templates select="@*|node()">
                <xsl:sort select="local-name()"/>
            </xsl:apply-templates>
        </xsl:copy>
    </xsl:template>

</xsl:stylesheet>

XML Output

<example>
   <djh><!-- comment --><?PI?>
      <baz>
         <bar>
            <baz/>
            <foo/>
         </bar>
         <foo>
            <bar/>
            <baz/>
         </foo>
      </baz>
      <foo attr="test">
         <bar>
            <baz>text</baz>
            <foo><!--comment--></foo>
         </bar>
         <baz attr="test">
            <bar/>
            <foo/>
         </baz>
      </foo>
   </djh>
   <next>
      <a>blabla</a>
      <c>blabla</c>
   </next>
   <note>
      <body>Don't forget me this weekend!</body>
      <from>Jani</from>
      <heada>head</heada>
      <headb>head</headb>
      <heading>Reminder</heading>
      <to>Tove</to>
   </note>
</example>

Notice though that comments and processing instructions end up floating to the top of the sort order.

Also note that if you have mixed content (element and text nodes in the same parent), you might want to skip the sorting of that element. Otherwise the text will come first in the sort order (like comments and processing instructions).

Here's a way to skip mixed content elements (comment and processing instruction output does change so you may want to experiment):

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:output indent="yes"/>
    <xsl:strip-space elements="*"/>

    <xsl:template match="@*|node()">
        <xsl:copy>
            <xsl:apply-templates select="@*|node()"/>            
        </xsl:copy>
    </xsl:template>

    <xsl:template match="*[not(text())]">
        <xsl:copy>
            <xsl:apply-templates select="@*|node()">
                <xsl:sort select="local-name()"/>
            </xsl:apply-templates>
        </xsl:copy>
    </xsl:template>

</xsl:stylesheet>

Note if you have multiple attributes on an element this solution errors with `XTDE0410: An attribute node (attr1) cannot be created after the children of the containing element` (using saxon at least) — stripybadger, Oct 10 '16 at 08:58

Sorting XML file by element

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