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<td valign="top" class="NAME">sum() Function</td>
<td valign="top" class="COMPATIBILITY">&nbsp;</td>
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<td colspan="2" class="divider"><img src="dwres:18084" width="100%" height="1"></td>
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Converts all nodes in the argument node-set to numbers, and then returns the sum of all of those numbers. If any node in the node-set can't be converted to numbers (passing them to the <span class="LITERAL">number()</span> function returns <span class="LITERAL">NaN</span>), the <span class="LITERAL">sum()</span> function returns <span class="LITERAL">NaN</span>. </td></tr>
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<td colspan="2" class="CLEARSEPARATION">&nbsp;</td>
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<td colspan="2" class="TITLE">Inputs</td>
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<p>A node-set. Any node in the node-set that is not a number is converted to a number as if it were passed to the <span class="LITERAL">number()</span> function, then the numeric values of all of the nodes are summed. </p>
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<td colspan="2" class="CLEARSEPARATION">&nbsp;</td>
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<td colspan="2" class="TITLE">Output</td>
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<p>The sum of the numeric values of all of the nodes in the argument node-set. If any node in the argument node-set cannot be converted to a number, the <span class="LITERAL">sum()</span> function returns <span class="LITERAL">NaN</span>.</p>
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<td colspan="2" class="TITLE">Defined in</td>
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<p>XPath section 4.4, Number Functions. </p>
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<td colspan="2" class="CLEARSEPARATION">&nbsp;</td>
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<td colspan="2" class="TITLE">Example</td>
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<p>We'll demonstrate the <span class="LITERAL">sum()</span> function against the following XML document:</p>
<span class="PROGRAMLISTING"><pre>
&lt;?xml version="1.0"?&gt;
&lt;report&gt;
  &lt;title&gt;Miles Flown in 2001&lt;/title&gt;
  &lt;month sequence="01"&gt;
    &lt;miles-flown&gt;12379&lt;/miles-flown&gt;
    &lt;miles-earned&gt;35215&lt;/miles-earned&gt;
  &lt;/month&gt;
  &lt;month sequence="02"&gt;
    &lt;miles-flown&gt;32857&lt;/miles-flown&gt;
    &lt;miles-earned&gt;92731&lt;/miles-earned&gt;
  &lt;/month&gt;
  &lt;month sequence="03"&gt;
    &lt;miles-flown&gt;19920&lt;/miles-flown&gt;
    &lt;miles-earned&gt;76725&lt;/miles-earned&gt;
  &lt;/month&gt;
  &lt;month sequence="04"&gt;
    &lt;miles-flown&gt;18903&lt;/miles-flown&gt;
    &lt;miles-earned&gt;31781&lt;/miles-earned&gt;
  &lt;/month&gt;
&lt;/report&gt;</pre></span>
<!--<?troff .Nd 10?>-->
<p>Here is a stylesheet that uses the <span class="LITERAL">sum()</span> function:</p>
<span class="PROGRAMLISTING"><pre>
&lt;?xml version="1.0"?&gt;
&lt;xsl:stylesheet version="1.0" 
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"&gt;

  &lt;xsl:output method="text"/&gt;

  &lt;xsl:variable name="newline"&gt;
&lt;xsl:text&gt;
&lt;/xsl:text&gt;
  &lt;/xsl:variable&gt;

  &lt;xsl:template match="/"&gt;
    &lt;xsl:value-of select="$newline"/&gt;
    &lt;xsl:text&gt;A test of the sum() function:&lt;/xsl:text&gt;

    &lt;xsl:value-of select="$newline"/&gt;
    &lt;xsl:value-of select="$newline"/&gt;
    &lt;xsl:text&gt;Total miles flown this year:  &lt;/xsl:text&gt;
    &lt;xsl:value-of 
      select="format-number(sum(/report/month/miles-flown), '###,###')"/&gt;
    &lt;xsl:value-of select="$newline"/&gt;
    &lt;xsl:value-of select="$newline"/&gt;
    &lt;xsl:text&gt;Total miles earned this year: &lt;/xsl:text&gt;
    &lt;xsl:value-of 
      select="format-number(sum(/report/month/miles-earned), '###,###')"/&gt;
    &lt;xsl:value-of select="$newline"/&gt;
    &lt;xsl:value-of select="$newline"/&gt;
  &lt;/xsl:template&gt;

&lt;/xsl:stylesheet&gt;</pre></span>
<p>Processing the XML document with this stylesheet generates these results:</p>
<span class="PROGRAMLISTING"><pre>

A test of the sum() function:

Total miles flown this year:  84,059

Total miles earned this year: 236,452
</pre></span>
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