mirror of
https://github.com/php/doc-zh.git
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267 lines
7.4 KiB
XML
267 lines
7.4 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<!-- $Revision$ -->
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<!-- EN-Revision: 9b1673cf114a1e10c4563ab9223cb56aed552b89 Maintainer: Gregory Status: ready -->
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<!-- CREDITS: mowangjuanzi, Luffy -->
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<refentry xmlns="http://docbook.org/ns/docbook" xml:id="function.utf8-decode">
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<refnamediv>
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<refname>utf8_decode</refname>
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<refpurpose>
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将字符串从 UTF-8 转换为 ISO-8859-1，替换无效或者无法表示的字符。
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</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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&warn.deprecated.function-8-2-0;
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</refsynopsisdiv>
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<refsect1 role="description">
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&reftitle.description;
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<methodsynopsis>
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<modifier role="attribute">#[\Deprecated]</modifier>
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<type>string</type><methodname>utf8_decode</methodname>
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<methodparam><type>string</type><parameter>string</parameter></methodparam>
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</methodsynopsis>
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<para>
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该函数将字符串 <parameter>string</parameter> 从 <literal>UTF-8</literal> 编码转换为
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<literal>ISO-8859-1</literal>。字符串中不是有效 UTF-8 字节或者不存在于 <literal>ISO-8859-1</literal>
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的 <literal>UTF-8</literal> 字符（即 <literal>U+00FF</literal> 以上的码点）将转化为 <literal>?</literal>。
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</para>
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<note>
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<para>
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Many web pages marked as using the <literal>ISO-8859-1</literal> character
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encoding actually use the similar <literal>Windows-1252</literal> encoding,
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and web browsers will interpret <literal>ISO-8859-1</literal> web pages as
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<literal>Windows-1252</literal>. <literal>Windows-1252</literal> features
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additional printable characters, such as the Euro sign
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(<literal>€</literal>) and curly quotes (<literal>“</literal>
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<literal>”</literal>), instead of certain <literal>ISO-8859-1</literal>
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control characters. This function will not convert such
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<literal>Windows-1252</literal> characters correctly. Use a different
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function if <literal>Windows-1252</literal> conversion is required.
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</para>
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</note>
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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>string</parameter></term>
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<listitem>
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<para>
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UTF-8 编码的字符串。
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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 <parameter>string</parameter> 的 ISO-8859-1 翻译。
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</para>
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</refsect1>
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<refsect1 role="changelog">
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&reftitle.changelog;
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<para>
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<informaltable>
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<tgroup cols="2">
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<thead>
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<row>
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<entry>&Version;</entry>
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<entry>&Description;</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry>8.2.0</entry>
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<entry>
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弃用此函数。
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</entry>
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</row>
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<row>
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<entry>7.2.0</entry>
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<entry>
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This function has been moved from the XML extension to the core of PHP.
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In previous versions, it was only available if the XML extension was installed.
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</entry>
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</row>
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</tbody>
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</tgroup>
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</informaltable>
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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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<example>
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<title>基础示例</title>
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<programlisting role="php">
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<![CDATA[
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<?php
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// Convert the string 'Zoë' from UTF-8 to ISO 8859-1
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$utf8_string = "\x5A\x6F\xC3\xAB";
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$iso8859_1_string = utf8_decode($utf8_string);
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echo bin2hex($iso8859_1_string), "\n";
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// Invalid UTF-8 sequences are replaced with '?'
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$invalid_utf8_string = "\xC3";
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$iso8859_1_string = utf8_decode($invalid_utf8_string);
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var_dump($iso8859_1_string);
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// Characters which don't exist in ISO 8859-1, such as
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// '€' (Euro Sign) are also replaced with '?'
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$utf8_string = "\xE2\x82\xAC";
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$iso8859_1_string = utf8_decode($utf8_string);
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var_dump($iso8859_1_string);
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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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5a6feb
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string(1) "?"
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string(1) "?"
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]]>
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</screen>
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</example>
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</refsect1>
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<refsect1 role="notes">
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&reftitle.notes;
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<note>
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<title>弃用和替代方案</title>
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<para>
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从 PHP 8.2.0 开始，<emphasis>弃用</emphasis>此函数，并将在未来的版本中删除。应检查现有用途并用适当的替代方案。
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</para>
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<para>
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类似的功能可以通过 <function>mb_convert_encoding</function> 实现，支持 ISO-8859-1 和许多其他字符编码。
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<informalexample>
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<programlisting role="php">
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<![CDATA[
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<?php
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$utf8_string = "\xC3\xAB"; // 'ë' (e with diaeresis) in UTF-8
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$iso8859_1_string = mb_convert_encoding($utf8_string, 'ISO-8859-1', 'UTF-8');
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echo bin2hex($iso8859_1_string), "\n";
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$utf8_string = "\xCE\xBB"; // 'λ' (Greek lower-case lambda) in UTF-8
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$iso8859_7_string = mb_convert_encoding($utf8_string, 'ISO-8859-7', 'UTF-8');
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echo bin2hex($iso8859_7_string), "\n";
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$utf8_string = "\xE2\x82\xAC"; // '€' (Euro sign) in UTF-8 (not present in ISO-8859-1)
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$windows_1252_string = mb_convert_encoding($utf8_string, 'Windows-1252', 'UTF-8');
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echo bin2hex($windows_1252_string), "\n";
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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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eb
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eb
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80
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]]>
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</screen>
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</informalexample>
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</para>
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<para>
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根据安装的扩展，其他有效选项是
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<methodname>UConverter::transcode</methodname> 和 <function>iconv</function>。
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</para>
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<para>
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以下都给出相同的结果：
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<informalexample>
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<programlisting role="php">
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<![CDATA[
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<?php
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$utf8_string = "\x5A\x6F\xC3\xAB"; // 'Zoë' in UTF-8
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$iso8859_1_string = utf8_decode($utf8_string);
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echo bin2hex($iso8859_1_string), "\n";
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$iso8859_1_string = mb_convert_encoding($utf8_string, 'ISO-8859-1', 'UTF-8');
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echo bin2hex($iso8859_1_string), "\n";
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$iso8859_1_string = iconv('UTF-8', 'ISO-8859-1', $utf8_string);
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echo bin2hex($iso8859_1_string), "\n";
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$iso8859_1_string = UConverter::transcode($utf8_string, 'ISO-8859-1', 'UTF8');
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echo bin2hex($iso8859_1_string), "\n";
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?>
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]]>
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</programlisting>
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&example.outputs;
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<screen>
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<![CDATA[
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5a6feb
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5a6feb
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5a6feb
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5a6feb
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]]>
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</screen>
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</informalexample>
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针对无效的字符串或者不能用 ISO 8859-1 表示的字符串，指定 <literal>'?'</literal> 作为
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<methodname>UConverter::transcode</methodname> 的 <literal>'to_subst'</literal>
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选项，将获得同 <function>utf8_decode</function> 相同的结果。
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<informalexample>
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<programlisting role="php">
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<![CDATA[
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<?php
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$utf8_string = "\xE2\x82\xAC"; // € (Euro Sign) does not exist in ISO 8859-1
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$iso8859_1_string = UConverter::transcode(
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$utf8_string, 'ISO-8859-1', 'UTF-8', ['to_subst' => '?']
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);
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var_dump($iso8859_1_string);
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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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sring(1) "?"
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]]>
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</screen>
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</informalexample>
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</para>
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</note>
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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>utf8_encode</function></member>
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<member><function>mb_convert_encoding</function></member>
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<member><methodname>UConverter::transcode</methodname></member>
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<member><function>iconv</function></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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