xpath_getelembytext.html
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<TITLE>Finding Elements by Content in a DOM Document Using XPath
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<h3>
e550.
Finding Elements by Content in a DOM Document Using XPath</h3>
XPath is an expression language for selecting nodes in an XML file.
See <a href="../org.w3c.dom/xpath_GetAbsElem.html" class="eglink"><font size="-1"><b>e548</b> Finding Elements by Absolute Location in a DOM Document Using XPath</font></a> for common XPath
expression for selecting elements. This example adds to those
examples by demonstrating the ability to select elements based on their
content.
<P> In an element such as <code><A>cat</A></code>, the content is simply
<code>"cat"</code>. However, in the case of an element that contains other
elements, the content is the concatenation of the content of all
subelements. For example, in the XML fragment
<code><A>cat<B>,<C>dog,</C>and</B>rat</A></code>,
the content of <code>A</code> is <code>"cat,dog,andrat"</code>.
<P> This example demonstrates some common uses of expressions that
use element content; for more information on XPath, see the
specification at <a href="http://www.w3c.org/TR/xpath"><font size="-1">http://www.w3c.org/TR/xpath</font></a>. In the example,
the result of an XPath expression is shown next to the expression; the
numbers are ids of elements in the sample file shown at the end of the
example.
<pre>
// Get all elements that equal the string cat
String xpath = "//*[.='cat']"; // 2 6
// Get all elements that equal the string dog
xpath = "//*[.='dog']"; // (none)
// Note that element #3 does not match because its
// content is <code>" dog "</code> rather than <code>"dog"</code>
// Get all elements that contain the string cat
xpath = "//*[contains(.,'cat')]"; // 1 2 4 5 6
// Get all elem3 elements that contain the string cat
xpath = "//elem3[contains(.,'cat')]"; // 6
// Get all elements that contain the string cat,
// ignoring the contents of any subelements
xpath = "//*[contains(child::text(),'cat')]"; // 2 4 6
// Get all elements without subelements and whose contents contains the string cat
xpath = "//*[count(*)=0 and contains(.,'cat')]"; // 2 6
</pre>
XPath 1.0 does not support case-insensitive matches. However,
a simple case-insensitive match can be done using the <code>translate()</code>
function, which converts a string by mapping one character into another:
<pre>
// Get all elements that contain the string cat, ignoring case
xpath = "//*[contains(translate(.,'abcdefghijklmnopqrstuvwxyz',"
+ " 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'),'CAT')]";
// 1 2 4 5 6 7
</pre>
To execute an XPath expression, see
<a href="../org.w3c.dom/xpath_GetAbsElem.html" class="eglink"><font size="-1"><b>e548</b> Finding Elements by Absolute Location in a DOM Document Using XPath</font></a>. Here is the sample XML file
used in the example:
<pre>
<?xml version="1.0" encoding="UTF-8"?>
<root id="1">
<elem1 id="2">cat</elem1>
<elem1 id="3"> dog </elem1>
<elem1 id="4">
cat
<elem2 id="5">
<elem3 id="6">cat</elem3>
</elem2>
dog
</elem1>
<elem1 id="7">Cat</elem1>
</root>
</pre>
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Related Examples
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e548. <a class="eglink" href="xpath_GetAbsElem.html?l=rel">
Finding Elements by Absolute Location in a DOM Document Using XPath
</a>
<br>
e549. <a class="eglink" href="xpath_GetChildElem.html?l=rel">
Selecting from a Set of Child Elements in a DOM Document Using XPath
</a>
<br>
e551. <a class="eglink" href="xpath_GetElemById.html?l=rel">
Finding Elements by Id in a DOM Document Using XPath
</a>
<br>
e552. <a class="eglink" href="xpath_GetElemByAttr.html?l=rel">
Finding Elements by Attributes in a DOM Document Using XPath
</a>
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See also:
<a class="eglink" href="/egs/org.w3c.dom/pkg.html?l=rel#Adding%20and%20Removing%20Nodes">
Adding and Removing Nodes
</a>
<a class="eglink" href="/egs/org.w3c.dom/pkg.html?l=rel#Element%20Attributes">
Element Attributes
</a>
<a class="eglink" href="/egs/org.w3c.dom/pkg.html?l=rel#Elements">
Elements
</a>
<a class="eglink" href="/egs/org.w3c.dom/pkg.html?l=rel#Getting%20Nodes">
Getting Nodes
</a>
<a class="eglink" href="/egs/org.w3c.dom/pkg.html?l=rel#Text%20Nodes">
Text Nodes
</a>
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