XPath Basics - Playing Chicken
(Page 6 of 9 )

Let's try a slightly more complex example:

<?xml version="1.0"?>




<recipe>




<name>Chicken Tikka</name>
<author>Anonymous</author>
<date>1 
June 1999</date>




<ingredients>




<item>
<desc>Boneless chicken breasts</desc>
<quantity>2</quantity>
</item>




<item>
<desc>Chopped onions</desc>
<quantity>2</quantity>
</item>




<item>
<desc>Ginger</desc>
<quantity>1 tsp</quantity>
</item>




<item>
<desc>Garlic</desc>
<quantity>1 tsp</quantity>
</item>




<item>
<desc>Red chili powder</desc>
<quantity>1 tsp</quantity>
</item>




<item>
<desc>Coriander seeds</desc>
<quantity>1 tsp</quantity>
</item>




<item>
<desc>Lime juice</desc>
<quantity>2 tbsp</quantity>
</item>




<item>
<desc>Butter</desc>
<quantity>1 tbsp</quantity>
</item>
</ingredients>




<servings>3</servings>




<process>
<step>Cut chicken into cubes, wash and apply lime juice and 
salt</step>
<step>Add ginger, garlic, chili, coriander and lime juice 
in a separate
bowl</step>
<step>Mix well, and add chicken to marinate 
for 3-4 hours</step>
<step>Place chicken pieces on skewers and barbeque</step>
<step>Remove, 
apply butter, and barbeque again until meat is tender</step>
<step>Garnish 
with lemon and chopped onions</step>
</process>




</recipe>

Now, if I wanted to get to the third ingredient, I would use the path

/recipe/ingredients/item[3]/desc/text()

whish references the text string

Ginger

Note the predicate used to get the third item in the list.

If I needed to get the number of servings, I could use

/recipe/servings/text()

or

//servings/text()

The // shortcut will select elements of that name anywhere below the current context node, and is equivalent to the "descendant-or-self" axis. So the path

//item

would select all the "item" nodes in the document, while the path

//item[7]/quantity

would reference the "quantity" element under the seventh "item" element and the path

//item[7]/quantity/text()

would reference the text node

2 tbsp

If I wanted to get really funky, I could use a different predicate to identify the appropriate node - the paths

//item[7]/quantity/text()

and

//item[desc/text()='Lime juice']/quantity/text()

are equivalent.

More examples of this nature are available in the XPath specification at http://www.w3.org/TR/xpath.html

This article copyright Melonfire 2001. All rights reserved.

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