next.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<!-- EN-Revision: 9d29b382865dca44919ae9803ef5dfdcbba185fe Maintainer: dallas Status: ready -->
  <refentry xml:id="function.next" xmlns="http://docbook.org/ns/docbook">
   <refnamediv>
    <refname>next</refname>
    <refpurpose>
     将数组中的内部指针向前移动一位
    </refpurpose>
   </refnamediv>
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>mixed</type><methodname>next</methodname>
   <methodparam><type class="union"><type>array</type><type>object</type></type><parameter role="reference">array</parameter></methodparam>
  </methodsynopsis>
   <para>
     <function>next</function> 和 <function>current</function>
     的行为类似，只有一点区别，在返回值之前将内部指针向前移动一位。这意味着它返回的是下一个数组单元的值并将数组指针向前移动了一位。
    </para>
   </refsect1>
    <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>array</parameter></term>
     <listitem>
      <para>
       受影响的 <type>array</type> 。
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   返回数组内部指针指向的下一个单元的值，或当没有更多单元时返回 &false;。
  </para>
  &return.falseproblem;
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <informaltable>
   <tgroup cols="2">
    <thead>
     <row>
      <entry>&Version;</entry>
      <entry>&Description;</entry>
     </row>
    </thead>
    <tbody>
     &standard.changelog.calling-on-objects;
    </tbody>
   </tgroup>
  </informaltable>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title> <function>next</function> 及相关函数的用法示例</title>
    <programlisting role="php">
<![CDATA[
<?php
$transport = array('foot', 'bike', 'car', 'plane');
$mode = current($transport); // $mode = 'foot';
$mode = next($transport);    // $mode = 'bike';
$mode = next($transport);    // $mode = 'car';
$mode = prev($transport);    // $mode = 'bike';
$mode = end($transport);     // $mode = 'plane';
?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>

 <refsect1 role="notes">
  &reftitle.notes;
  <note>
   <simpara>
    很难区别是到了数组尾部还是元素为 <type>bool</type> &false; 。要正确遍历可能含有 &false; 单元的数组，参见 
    <link linkend="control-structures.foreach"><literal>foreach</literal></link> 函数。
   </simpara>
   <simpara>
    仍要使用 <function>next</function> 并正确检测是否到了数组尾部，需要检查 <function>key</function> 是否为 &null;。
   </simpara>
  </note>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>current</function></member>
    <member><function>end</function></member>
    <member><function>prev</function></member>
    <member><function>reset</function></member>
    <member><function>each</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>
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