(PHP 4, PHP 5, PHP 7, PHP 8)
utf8_decode — 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。
此函数自 PHP 8.2.0 起弃用。强烈建议不要应用此函数。
该函数将字符串 string 从 UTF-8 编码转换为
ISO-8859-1。字符串中不是有效 UTF-8 字节或者不存在于 ISO-8859-1
的 UTF-8 字符（即 U+00FF 以上的码点）将转化为 ?。
注意:
Many web pages marked as using the
ISO-8859-1character encoding actually use the similarWindows-1252encoding, and web browsers will interpretISO-8859-1web pages asWindows-1252.Windows-1252features additional printable characters, such as the Euro sign (€) and curly quotes (“”), instead of certainISO-8859-1control characters. This function will not convert suchWindows-1252characters correctly. Use a different function ifWindows-1252conversion is required.
stringUTF-8 编码的字符串。
返回 string 的 ISO-8859-1 翻译。
| 版本 | 说明 |
|---|---|
| 8.2.0 | 弃用此函数。 |
| 7.2.0 | This function has been moved from the XML extension to the core of PHP. In previous versions, it was only available if the XML extension was installed. |
示例 #1 基础示例
<?php
// Convert the string 'Zoë' from UTF-8 to ISO 8859-1
$utf8_string = "\x5A\x6F\xC3\xAB";
$iso8859_1_string = utf8_decode($utf8_string);
echo bin2hex($iso8859_1_string), "\n";
// Invalid UTF-8 sequences are replaced with '?'
$invalid_utf8_string = "\xC3";
$iso8859_1_string = utf8_decode($invalid_utf8_string);
var_dump($iso8859_1_string);
// Characters which don't exist in ISO 8859-1, such as
// '€' (Euro Sign) are also replaced with '?'
$utf8_string = "\xE2\x82\xAC";
$iso8859_1_string = utf8_decode($utf8_string);
var_dump($iso8859_1_string);
?>以上示例会输出：
5a6feb string(1) "?" string(1) "?"
注意: 弃用和替代方案
从 PHP 8.2.0 开始，弃用此函数，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。
类似的功能可以通过 mb_convert_encoding() 实现，支持 ISO-8859-1 和许多其他字符编码。
<?php
$utf8_string = "\xC3\xAB"; // 'ë' (e with diaeresis) in UTF-8
$iso8859_1_string = mb_convert_encoding($utf8_string, 'ISO-8859-1', 'UTF-8');
echo bin2hex($iso8859_1_string), "\n";
$utf8_string = "\xCE\xBB"; // 'λ' (Greek lower-case lambda) in UTF-8
$iso8859_7_string = mb_convert_encoding($utf8_string, 'ISO-8859-7', 'UTF-8');
echo bin2hex($iso8859_7_string), "\n";
$utf8_string = "\xE2\x82\xAC"; // '€' (Euro sign) in UTF-8 (not present in ISO-8859-1)
$windows_1252_string = mb_convert_encoding($utf8_string, 'Windows-1252', 'UTF-8');
echo bin2hex($windows_1252_string), "\n";
?>以上示例会输出：
eb eb 80根据安装的扩展，其他有效选项是 UConverter::transcode() 和 iconv()。
以下都给出相同的结果：
针对无效的字符串或者不能用 ISO 8859-1 表示的字符串，指定<?php
$utf8_string = "\x5A\x6F\xC3\xAB"; // 'Zoë' in UTF-8
$iso8859_1_string = utf8_decode($utf8_string);
echo bin2hex($iso8859_1_string), "\n";
$iso8859_1_string = mb_convert_encoding($utf8_string, 'ISO-8859-1', 'UTF-8');
echo bin2hex($iso8859_1_string), "\n";
$iso8859_1_string = iconv('UTF-8', 'ISO-8859-1', $utf8_string);
echo bin2hex($iso8859_1_string), "\n";
$iso8859_1_string = UConverter::transcode($utf8_string, 'ISO-8859-1', 'UTF8');
echo bin2hex($iso8859_1_string), "\n";
?>以上示例会输出：
5a6feb 5a6feb 5a6feb 5a6feb'?'作为 UConverter::transcode() 的'to_subst'选项，将获得同 utf8_decode() 相同的结果。<?php
$utf8_string = "\xE2\x82\xAC"; // € (Euro Sign) does not exist in ISO 8859-1
$iso8859_1_string = UConverter::transcode(
$utf8_string, 'ISO-8859-1', 'UTF-8', ['to_subst' => '?']
);
var_dump($iso8859_1_string);
?>以上示例会输出：
sring(1) "?"