XPath Number Operators

XPath also includes a range of operators you can take advantage of when using number values within your expressions.

Number Operators

Number Functions

Usage Example

The Source XML File

We'll use the following XML file, which contains a list of vegetables and their associated nutritional value:


<?xml version="1.0"?>
<food_list>
  <food_item type="vegetable">
    <name>Agar</name>
    <carbs_per_serving>81</carbs_per_serving>
    <fiber_per_serving>8</fiber_per_serving>
    <fat_per_serving>0.5</fat_per_serving>
    <kj_per_serving>1280</kj_per_serving>
  </food_item>
  <food_item type="vegetable">
    <name>Asparagus</name>
    <carbs_per_serving>1</carbs_per_serving>
    <fiber_per_serving>1</fiber_per_serving>
    <fat_per_serving>0</fat_per_serving>
    <kj_per_serving>40</kj_per_serving>
  </food_item>
  <food_item type="vegetable">
    <name>Cabbage</name>
    <carbs_per_serving>0</carbs_per_serving>
    <fiber_per_serving>1</fiber_per_serving>
    <fat_per_serving>0</fat_per_serving>
    <kj_per_serving>14</kj_per_serving>
  </food_item>
  <food_item type="vegetable">
    <name>Potato</name>
    <carbs_per_serving>21.5</carbs_per_serving>
    <fiber_per_serving>2</fiber_per_serving>
    <fat_per_serving>1</fat_per_serving>
    <kj_per_serving>460</kj_per_serving>
  </food_item>
  <food_item type="vegetable">
    <name>Pumpkin</name>
    <carbs_per_serving>6</carbs_per_serving>
    <fiber_per_serving>1</fiber_per_serving>
    <fat_per_serving>0.5</fat_per_serving>
    <kj_per_serving>150</kj_per_serving>
  </food_item>
  <food_item type="vegetable">
    <name>Yam</name>
    <carbs_per_serving>30.5</carbs_per_serving>
    <fiber_per_serving>2</fiber_per_serving>
    <fat_per_serving>0.5</fat_per_serving>
    <kj_per_serving>550</kj_per_serving>
  </food_item>
  <food_item type="vegetable">
    <name>Zucchini</name>
    <carbs_per_serving>1.5</carbs_per_serving>
    <fiber_per_serving>1.5</fiber_per_serving>
    <fat_per_serving>0.5</fat_per_serving>
    <kj_per_serving>55</kj_per_serving>
  </food_item>
</food_list>

The Requirement

This time, for each record, we'll display the carbohydrate value ("carbs"). We will also display a column that multiplies the number of carbs by 3 (representing 3 meals per day). Like this:

The Solution

We could modify the code from the previous lesson so that only the top 5 records are selected. We could achieve this using the XPath <= operator (along with the position() function), as follows:


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

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

<xsl:template match="food_list">
  <table border="1" style="background-color:#cccc00">
    <tr>
      <th>Food Item</th>
      <th>Carbs Per Serving</th>
      <th>Carbs Per Day (3 serves per day)</th>
    </tr>
    <xsl:for-each select="food_item">
      <tr>
        <td><xsl:value-of select="name"/></td>
        <td><xsl:value-of select="carbs_per_serving"/></td>
        <td><xsl:value-of select="carbs_per_serving * 3"/></td>
      </tr>
    </xsl:for-each>
  </table>
</xsl:template>

</xsl:stylesheet>

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