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470e6fe62f
git-svn-id: https://svn.php.net/repository/phpdoc/zh/trunk@333633 c90b9560-bf6c-de11-be94-00142212c4b1
367 lines
7.7 KiB
XML
Executable File
367 lines
7.7 KiB
XML
Executable File
<?xml version="1.0" encoding="utf-8"?>
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<!-- $Revision$ -->
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<!-- EN-Revision: 5faa7a6747bca628b3bdcc9f93aec5603b65581f Maintainer: HonestQiao Status: ready -->
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<!-- Reviewed: no Maintainer: HonestQiao -->
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<refentry xml:id="function.array-map" xmlns="http://docbook.org/ns/docbook">
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<refnamediv>
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<refname>array_map</refname>
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<refpurpose>
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将回调函数作用到给定数组的单元上
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</refpurpose>
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</refnamediv>
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<refsect1 role="description">
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&reftitle.description;
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<methodsynopsis>
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<type>array</type><methodname>array_map</methodname>
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<methodparam><type>callable</type><parameter>callback</parameter></methodparam>
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<methodparam><type>array</type><parameter>arr1</parameter></methodparam>
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<methodparam choice="opt"><type>array</type><parameter>...</parameter></methodparam>
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</methodsynopsis>
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<para>
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<function>array_map</function> 返回一个数组，该数组包含了
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<parameter>arr1</parameter> 中的所有单元经过
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<parameter>callback</parameter> 作用过之后的单元。<parameter>callback</parameter>
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接受的参数数目应该和传递给
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<function>array_map</function> 函数的数组数目一致。
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</para>
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</refsect1>
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<refsect1 role="parameters">
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&reftitle.parameters;
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<para>
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<variablelist>
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<varlistentry>
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<term><parameter>callback</parameter></term>
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<listitem>
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<para>
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对每个数组的每个元素作用的回调函数。
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>arr1</parameter></term>
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<listitem>
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<para>
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将被回调函数（<parameter>callback</parameter>）执行的数组。
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>array</parameter></term>
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<listitem>
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<para>
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将被回调函数（<parameter>callback</parameter>）执行的数组列表。
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</para>
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</refsect1>
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<refsect1 role="returnvalues">
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&reftitle.returnvalues;
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<para>
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返回一个数组，该数组的每个元素都数组（<parameter>arr1</parameter>）里面的每个元素经过回调函数（<parameter>callback</parameter>）处理了的。
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</para>
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</refsect1>
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<refsect1 role="examples">
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&reftitle.examples;
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<para>
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<example>
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<title><function>array_map</function> 例子</title>
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<programlisting role="php">
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<![CDATA[
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<?php
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function cube($n)
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{
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return($n * $n * $n);
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}
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$a = array(1, 2, 3, 4, 5);
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$b = array_map("cube", $a);
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print_r($b);
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?>
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]]>
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</programlisting>
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<para>
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这使得 <varname>$b</varname> 成为：
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</para>
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<screen>
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<![CDATA[
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Array
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(
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[0] => 1
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[1] => 8
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[2] => 27
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[3] => 64
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[4] => 125
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)
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]]>
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</screen>
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</example>
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</para>
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<para>
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<example>
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<title><function>array_map</function> using a lambda function (as of PHP 5.3.0)</title>
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<programlisting role="php">
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<![CDATA[
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<?php
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$func = function($value) {
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return $value * 2;
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};
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print_r(array_map($func, range(1, 5)));
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?>
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]]>
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</programlisting>
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<screen>
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<![CDATA[
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Array
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(
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[0] => 2
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[1] => 4
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[2] => 6
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[3] => 8
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[4] => 10
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)
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]]>
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</screen>
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</example>
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</para>
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<para>
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<example>
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<title><function>array_map</function> - 使用更多的数组</title>
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<programlisting role="php">
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<![CDATA[
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<?php
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function show_Spanish($n, $m)
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{
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return("The number $n is called $m in Spanish");
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}
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function map_Spanish($n, $m)
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{
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return(array($n => $m));
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}
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$a = array(1, 2, 3, 4, 5);
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$b = array("uno", "dos", "tres", "cuatro", "cinco");
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$c = array_map("show_Spanish", $a, $b);
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print_r($c);
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$d = array_map("map_Spanish", $a , $b);
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print_r($d);
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?>
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]]>
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</programlisting>
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&example.outputs;
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<screen>
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<![CDATA[
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// printout of $c
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Array
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(
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[0] => The number 1 is called uno in Spanish
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[1] => The number 2 is called dos in Spanish
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[2] => The number 3 is called tres in Spanish
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[3] => The number 4 is called cuatro in Spanish
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[4] => The number 5 is called cinco in Spanish
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)
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// printout of $d
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Array
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(
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[0] => Array
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(
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[1] => uno
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)
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[1] => Array
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(
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[2] => dos
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)
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[2] => Array
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(
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[3] => tres
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)
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[3] => Array
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(
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[4] => cuatro
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)
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[4] => Array
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(
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[5] => cinco
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)
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)
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]]>
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</screen>
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</example>
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</para>
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<para>
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通常使用了两个或更多数组时，它们的长度应该相同，因为回调函数是平行作用于相应的单元上的。如果数组的长度不同，则最短的一个将被用空的单元扩充。
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</para>
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<para>
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本函数一个有趣的用法是构造一个数组的数组，这可以很容易的通过用 &null; 作为回调函数名来实现。
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</para>
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<para>
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<example>
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<title>建立一个数组的数组</title>
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<programlisting role="php">
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<![CDATA[
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<?php
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$a = array(1, 2, 3, 4, 5);
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$b = array("one", "two", "three", "four", "five");
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$c = array("uno", "dos", "tres", "cuatro", "cinco");
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$d = array_map(null, $a, $b, $c);
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print_r($d);
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?>
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]]>
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</programlisting>
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&example.outputs;
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<screen>
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<![CDATA[
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Array
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(
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[0] => Array
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(
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[0] => 1
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[1] => one
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[2] => uno
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)
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[1] => Array
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(
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[0] => 2
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[1] => two
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[2] => dos
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)
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[2] => Array
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(
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[0] => 3
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[1] => three
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[2] => tres
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)
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[3] => Array
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(
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[0] => 4
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[1] => four
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[2] => cuatro
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)
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[4] => Array
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(
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[0] => 5
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[1] => five
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[2] => cinco
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)
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)
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]]>
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</screen>
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</example>
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</para>
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<para>
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如果数组参数里面有字符串的键，那么返回的数组就会包含字符串的键，仅且仅当只传入一个数组的时候（试了下，就是原数组返回，没变化啊，这不是蛋疼么？）。
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如果不止一个数组被传入，那么返回的数组的的键都是整型。
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</para>
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<para>
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<example>
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<title><function>array_map</function> - with string keys</title>
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<programlisting role="php">
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<![CDATA[
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<?php
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$arr = array("stringkey" => "value");
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function cb1($a) {
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return array ($a);
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}
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function cb2($a, $b) {
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return array ($a, $b);
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}
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var_dump(array_map("cb1", $arr));
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var_dump(array_map("cb2", $arr, $arr));
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var_dump(array_map(null, $arr));
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var_dump(array_map(null, $arr, $arr));
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?>
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]]>
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</programlisting>
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&example.outputs;
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<screen>
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<![CDATA[
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array(1) {
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["stringkey"]=>
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array(1) {
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[0]=>
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string(5) "value"
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}
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}
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array(1) {
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[0]=>
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array(2) {
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[0]=>
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string(5) "value"
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[1]=>
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string(5) "value"
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}
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}
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array(1) {
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["stringkey"]=>
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string(5) "value"
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}
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array(1) {
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[0]=>
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array(2) {
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[0]=>
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string(5) "value"
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[1]=>
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string(5) "value"
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}
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}
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]]>
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</screen>
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</example>
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</para>
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</refsect1>
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<refsect1 role="seealso">
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&reftitle.seealso;
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<para>
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<simplelist>
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<member><function>array_filter</function></member>
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<member><function>array_reduce</function></member>
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<member><function>array_walk</function></member>
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<member><function>create_function</function></member>
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<member>&seealso.callback;</member>
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</simplelist>
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</para>
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</refsect1>
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</refentry>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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sgml-omittag:t
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sgml-shorttag:t
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sgml-minimize-attributes:nil
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sgml-always-quote-attributes:t
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sgml-indent-step:1
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sgml-indent-data:t
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indent-tabs-mode:nil
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sgml-parent-document:nil
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sgml-default-dtd-file:"~/.phpdoc/manual.ced"
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sgml-exposed-tags:nil
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sgml-local-catalogs:nil
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sgml-local-ecat-files:nil
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End:
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vim600: syn=xml fen fdm=syntax fdl=2 si
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vim: et tw=78 syn=sgml
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vi: ts=1 sw=1
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-->
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