<xsl:if> Example

XSLT <if> Element

The XSLT <xsl:if> element allows you to perform conditional statements against the contents of your XML document. For example, you can present different content only if a given condition is met.

This element can be used in conjunction with the <xsl:for-each> element to present different content depending on the contents of the XML file.

<xsl:if> Example

The Source File

Imagine have an XML file containing a list of food and it's nutritional value. Something like this:

 <?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_item type="seafood">     <name>Abalone</name>     <carbs_per_serving>0</carbs_per_serving>     <fiber_per_serving>0</fiber_per_serving>     <fat_per_serving>1</fat_per_serving>     <kj_per_serving>400</kj_per_serving>   </food_item>   <food_item type="seafood">     <name>Barramundi</name>     <carbs_per_serving>0</carbs_per_serving>     <fiber_per_serving>0</fiber_per_serving>     <fat_per_serving>2</fat_per_serving>     <kj_per_serving>390</kj_per_serving>   </food_item>   <food_item type="fruit">     <name>Apple</name>     <carbs_per_serving>15</carbs_per_serving>     <fiber_per_serving>2.5</fiber_per_serving>     <fat_per_serving>0</fat_per_serving>     <kj_per_serving>250</kj_per_serving>   </food_item>   <food_item type="fruit">     <name>Kiwi Fruit</name>     <carbs_per_serving>7.5</carbs_per_serving>     <fiber_per_serving>2.5</fiber_per_serving>     <fat_per_serving>0</fat_per_serving>     <kj_per_serving>150</kj_per_serving>   </food_item>   <food_item type="grain">     <name>Oatbran</name>     <carbs_per_serving>62</carbs_per_serving>     <fiber_per_serving>14</fiber_per_serving>     <fat_per_serving>7</fat_per_serving>     <kj_per_serving>1400</kj_per_serving>   </food_item>   <food_item type="grain">     <name>Wheatgerm</name>     <carbs_per_serving>1.5</carbs_per_serving>     <fiber_per_serving>1</fiber_per_serving>     <fat_per_serving>0.5</fat_per_serving>     <kj_per_serving>70</kj_per_serving>   </food_item> </food_list> 

The Requirement

Now, imagine we're only interested in the vegetables - we only want to display the food that have a type attribute of "vegetable". And, we also want to display it nicely formatted in an HTML table. Something like this:

The Solution

To achieve the above outcome, we use <xsl:for-each> to loop through each "food_item" element, and <xsl:if> to check the value of the "type" attribute (we do this by using the @ symbol - that's how you specify an attribute). If the attribute value equals "vegetable" we output the details.

 <?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>     <tr style="background-color:#ccff00">       <th>Food Item</th>       <th>Carbs (g)</th>       <th>Fiber (g)</th>       <th>Fat (g)</th>       <th>Energy (kj)</th>     </tr>     <xsl:for-each select="food_item">       <xsl:if test="@type = 'vegetable'">         <tr style="background-color:#00cc00">           <td><xsl:value-of select="name"/></td>           <td><xsl:value-of select="carbs_per_serving"/></td>           <td><xsl:value-of select="fiber_per_serving"/></td>           <td><xsl:value-of select="fat_per_serving"/></td>           <td><xsl:value-of select="kj_per_serving"/></td>        </tr>       </xsl:if>     </xsl:for-each>   </table> </xsl:template>  </xsl:stylesheet>