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XPath Predicate

XPath Predicate​

XPath Predicate refers to the XPath expression written in square brackets. It refers to restrict the selected nodes in a node set for some condition.

XPath Predicates are used to find a specific node or a node that contains a specific value.

note

XPath Predicates are always embedded in square brackets.

Example​

Consider the following XML document:

<?xml version="1.0"  encoding="UTF-8"?>

<bookstore>
    <book>
        <title lang="en">A Great Book</title>
        <author>Tom Nolan</author>
        <price>19.99</price>
    </book>

    <book>
        <title lang="en">Learning XML</title>
        <author>Tutorial Reference</author>
        <price>29.99</price>
    </book>
</bookstore>

In the following table there are some path expressions with predicates and the result of the expressions:

Path ExpressionResult
/bookstore/book[1]Selects the first book element that is the child of the bookstore element.
/bookstore/book[last()]Selects the last book element that is the child of the bookstore element
/bookstore/book[last()-1]Selects the last but one book element that is the child of the bookstore element
/bookstore/book[position()<3]Selects the first two book elements that are children of the bookstore element
//title[@lang]Selects all the title elements that have an attribute named lang
//title[@lang='en']Selects all the title elements that have a "lang" attribute with a value of "en"
/bookstore/book[price>15.00]Selects all the book elements of the bookstore element that have a price element with a value greater than 15.00
/bookstore/book[price>15.00]/titleSelects all the title elements of the book elements of the bookstore element that have a price element with a value greater than 15.00
note

In IE 5,6,7,8,9 first node is[0], but according to W3C, it is [1].

To solve this problem in IE, set the SelectionLanguage to XPath.

In JavaScript you can do in this way: xml.setProperty("SelectionLanguage","XPath");

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