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<?xml version="1.0" encoding="ISO-8859-1"?>
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- Copyright (C) 1998-2018 OpenLink Software
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- under the terms of the GNU General Public License as published by the
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-->
<refentry id="xpf_avg">
<refmeta>
<refentrytitle>avg</refentrytitle>
<refmiscinfo>XPATH</refmiscinfo>
</refmeta>
<refnamediv>
<refname>avg</refname>
<refpurpose>Returns average value of all its arguments.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis id="xpf_syn_avg">
<funcprototype id="xpf_proto_avg">
<funcdef>number <function>avg</function></funcdef>
<paramdef><parameter>arg1</parameter> any</paramdef>
<paramdef><parameter>arg2</parameter> any</paramdef>
<paramdef><parameter>...</parameter></paramdef>
<paramdef><parameter>argN</parameter> any</paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 id="xpf_desc_avg"><title>Description</title>
<para>
The function returns the average of all values in all its arguments,
For each node in every argument node-set, it converts the string-value of the node to a number and adds the result to the sum.
If some arguments are not node-sets, they are converted to numbers first and added to the sum.
Then sum is divided by number of values added and the result is returned.
</para>
<para>
This function is not a part of XPATH 1.0 standard library.
</para>
</refsect1>
<refsect1 id="xpf_params_avg"><title>Parameters</title>
<refsect2><title>argI</title>
<para>A node-set of nodes whose string values must be converted to numbers and added to the result, or single value.</para></refsect2>
</refsect1>
<refsect1 id="xpf_ret_avg"><title>Return Types</title><para></para></refsect1>
<table><title>Errors signalled by</title>
<tgroup cols="4">
<thead><row><entry>SQLState</entry><entry>Error Code</entry><entry>Error Text</entry><entry>Description</entry></row></thead>
<tbody>
<row>
<entry><errorcode>XP001</errorcode></entry>
<entry><errorcode>XPF06</errorcode></entry>
<entry><errorname>Nonempty sequence of values expected as argument(s) of XPATH function avg(); avg() of nothing is senseless</errorname></entry>
<entry>This happens if the function is called without arguments, or with all arguments set to empty node-sets.</entry>
</row>
</tbody>
</tgroup>
</table>
<refsect1 id="xpf_examples_avg"><title>Examples</title>
<example id="xpf_ex_avg"><title></title>
<para></para>
<screen>avg(/report[@type="daily-sales"]/total)</screen>
</example>
</refsect1>
<refsect1 id="xpf_seealso_avg"><title>See Also</title>
<para><link linkend="xpf_sum">sum</link><link linkend="xpf_max">max</link><link linkend="xpf_min">min</link></para>
</refsect1>
</refentry>
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