• Chapter 1: Getting Started with Stylus Studio
• Chapter 2: Editing and Querying XML
• Chapter 3: Converting Non-XML Files to XML
• Chapter 4: Working with XSLT
• Chapter 5: Creating XSLT Using the XSLT Mapper
• Chapter 6: Debugging Stylesheets
• Chapter 7: Defining XML Schemas
• Chapter 8: Defining Document Type Definitions
• Chapter 9: Writing XPath Expressions
  • About the XPath Processor
  • Sample Data for Examples and Testing
  • Getting Started with Queries
  • Specifying the Nodes to Evaluate
  • Handling Strings and Text
  • Specifying Boolean Expressions and Functions
  • Specifying Number Operations and Functions
  • Comparing Values
  • Finding a Particular Node
  • Obtaining a Union
  • Obtaining Information About a Node or a Node Set
  • Using XPath Expressions in Stylesheets
  • Accessing Other Documents During Query Execution
  • XPath Quick Reference
• Chapter 10: Working with XQuery in Stylus Studio
• Chapter 11: Composing Web Service Calls
• Chapter 12: Accessing Relational Data as XML
• Chapter 13: Extending Stylus Studio
• Chapter 14: Stylus Studio Reference

Home > Online Product Documentation > Table of Contents > Finding the First Node That Meets a Condition

Finding the First Node That Meets a Condition

Suppose you want to obtain from a collection the first node that meets a certain condition. For example, you want the first book whose author's last name is Bob. You can specify the following query:

(//book[author/last-name="Bob"])[position()=1]
               

            

When the XPath processor evaluates this expression, it creates a collection of book elements where the author's last name is Bob. The XPath processor then returns the first node in this collection.

The following two expressions appear to also return the first book whose author's last name is Bob, but they do not. Instead, these queries both return a book whose author's last name is Bob only if that book is the first book in the document.

//book[author/first-name="Bob"][position()=1]
               
//book[author/first-name="Bob" and position() = 1]