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<?xml version="1.0" encoding="ISO-8859-1"?>
<!--
-
- This file is part of the OpenLink Software Virtuoso Open-Source (VOS)
- project.
-
- Copyright (C) 1998-2018 OpenLink Software
-
- This project is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by the
- Free Software Foundation; only version 2 of the License, dated June 1991.
-
- This program is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
-
- You should have received a copy of the GNU General Public License along
- with this program; if not, write to the Free Software Foundation, Inc.,
- 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
-
-
-->
<refentry id="xpf_number">
<refmeta>
<refentrytitle>number</refentrytitle>
<refmiscinfo>XPATH</refmiscinfo>
</refmeta>
<refnamediv>
<refname>number</refname>
<refpurpose>Converts its argument to a number.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis id="xpf_syn_number">
<funcprototype id="xpf_proto_number">
<funcdef>number <function>number</function></funcdef>
<paramdef><optional><parameter>obj</parameter> any</optional></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 id="xpf_desc_number"><title>Description</title>
<para>
The number function converts its argument to a number as follows:
</para>
<itemizedlist mark="bullet" spacing="compact">
<listitem><para>
A string that consists of decimal number and optional whitespaces is converted to the number recorded.
Any other string is converted to NaN ("not-a-number" value).
More precisely,
a string that consists of
optional whitespace followed by an optional plus or minus sign
followed by a Number followed by whitespace is converted to the
IEEE 754 number that is nearest
(according to the IEEE 754 round-to-nearest rule)
to the mathematical value represented by the string.
Note that it differs from XPATH 1.0 standard where plus sign is not allowed
before Number part of the string.
</para></listitem>
<listitem><para>
Boolean true is converted to 1; boolean false is converted to 0.
</para></listitem>
<listitem><para>
A node-set is first converted to a string as if by a call to the string function and then converted in the same way as a string argument.
</para></listitem>
<listitem><para>
An object of a type other than the four basic types is converted to a number in a way that is dependent on that type.
</para></listitem>
</itemizedlist>
<para>
If the argument is omitted, it defaults to a node-set with the context node as its only member.
</para>
</refsect1>
<refsect1 id="xpf_params_number"><title>Parameters</title>
<refsect2><title>obj</title>
<para>Value to be converted to a number.</para></refsect2>
</refsect1>
<refsect1 id="xpf_ret_number"><title>Return Types</title><para>Number</para></refsect1>
<refsect1 id="xpf_examples_number"><title>Examples</title>
<example id="xpf_ex_number"><title></title>
<para></para>
<screen>number(' 3.1415926 ')</screen>
</example>
</refsect1>
<refsect1 id="xpf_seealso_number"><title>See Also</title>
<para><link linkend="xpf_string">string()</link><link linkend="xpf_boolean">boolean()</link></para>
</refsect1>
</refentry>
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