XML Filtering Predicate

I need to filter some XML data based on several conditions. I found the following article “”http://www.darronschall.com/weblog/archives/000214.cfm">E4X: Predicate Filtering with Regular Expressions" from Darron that provides a nice overview of filtering using e4x. I haven’t found any more detailed information on using predicates so I checked out the ECMAScript for XML
(E4X) Specification 2nd edition. See page 52 for details. But in short the filter can be an expression and use && and ||, the logical and and or.

filtered = list.item.( /^4567.*/.test( number ) || /^D.*/.test( name ) );

Here is the full test case:

package tests.actionscript
{

import flexunit.framework.*;

public class TestXml extends TestCase
{

public function testXMLFiltering():void {
 var list:XML =  <list>  
  <item>
     <name>Kamesh</name>
     <number>12345</number>
 </item>
 <item>
     <name>Daniel</name>
     <number>12345</number>
 </item>
 <item>
     <name>Robin</name>
     <number>12345</number>
 </item>
 <item>
     <name>George</name>
     <number>4567</number>
 </item>
 <item>
     <name>Adam</name>
     <number>4567</number>
 </item>
 <item>
     <name>Dean</name>
     <number>4567</number>
     <policy>yes</policy>
 </item>
 </list>

var filtered:XMLList = list.item.( /^D.*/.test( name ) ); Assert.assertEquals(2, new XMLListCollection(filtered).length);
filtered = list.item.( /^4567.*/.test( number ) ); 
Assert.assertEquals(3, new XMLListCollection(filtered).length);

filtered = list.item.( /^4567.*/.test( number ) && /^D.*/.test( name ) ); 
Assert.assertEquals(1, new XMLListCollection(filtered).length);

filtered = list.item.( /^4567.*/.test( number ) || /^D.*/.test( name ) ); 
Assert.assertEquals(4, new XMLListCollection(filtered).length);

}

} // class

} // package

Posted by Daniel Wanja Tue, 27 Feb 2007 22:31:00 GMT

Read full article 2 comments


Comments

  1. tom about 1 year later:

    how would I do the same thing if instead of a node named “number” I had a name with special characters, e.g. “number-number”.

    I’ve tried .test( number-number ) but doesn’t work

    thank you

  2. Daniel Wanja about 1 year later:

    I haven’t tried but it should be something like .text(attribute(‘number-number’)==‘123’);