如何使用XQuery从一系列值中选择属性的特定值？

Question

How do I select a specific attribute value from a series of values using XQuery?

My XML file looks like this:

<unit id="01" xref="entry01 entry02">

How do I select a specific value -- such as entry01 --- from the xref attribute and assign it to a variable?

I need to select the individual values from the attribute xref , because additional features for these values are defined later in the file:

<features xref="entry01" font-size="2">
<features xref="entry02" font-size="3">

I would like to organize the entries into a table such as one exemplified below. The columns defined by the attributes as follows: unit id, xref, font-size.

<tbody>
<tr>
<td>01</td>
<td>entry01</td>
<td>2</td>
</tr>
<tr>
<td>01</td>
<td>entry02</td>
<td>3</td>
</tr>
</tbody>

Answer 1

Use fn:tokenize to split at space (or all whitespace) characters, depending on you needs:

Split at a single space:

tokenize(<unit id="01" xref="entry01 entry02"/>/@xref, " ")[1]

Allow multiple spaces directly following each other:

tokenize(<unit id="01" xref="entry01  entry02"/>/@xref, " +")[2

Split at a single whitespace (I changed the attribute value to contain a tab character):

tokenize(<unit id="01" xref="entry01    entry02"/>/@xref, "\s")[2]