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(PHP 5 >= 5.5.0, PHP 7, PHP 8, PECL >= 3.0.0a1)
UConverter::transcode — Convert a string from one character encoding to another
$str,$toEncoding,$fromEncoding,$options = null
Converts str from fromEncoding to toEncoding.
str
The string to be converted.
toEncoding
The desired encoding of the result.
fromEncoding
The current encoding used to interpret str.
options
An optional array, which may contain the following keys:
'to_subst' - the substitution character to use
in place of any character of str which cannot
be encoded in toEncoding. If specified, it must
represent a single character in the target encoding.
Returns the converted string 或者在失败时返回 false.
示例 #1 Converting from UTF-8 to UTF-16 and back
<?php
$utf8_string = "\x5A\x6F\xC3\xAB"; // 'Zoë' in UTF-8
$utf16_string = UConverter::transcode($utf8_string, 'UTF-16BE', 'UTF-8');
echo bin2hex($utf16_string), "\n";
$new_utf8_string = UConverter::transcode($utf16_string, 'UTF-8', 'UTF-16BE');
echo bin2hex($new_utf8_string), "\n";
?>
以上例程会输出：
005a006f00eb 5a6fc3ab
示例 #2 Invalid characters in input
If the input string contains a sequence of bytes which is not valid in
the encoding specified by fromEncoding, they are
replaced by Unicode code point U+FFFD (Replacement Character) before
converting to toEncoding.
<?php
$invalid_utf8_string = "\xC3"; // incomplete multi-byte UTF-8 sequence
$utf16_string = UConverter::transcode($invalid_utf8_string, 'UTF-16BE', 'UTF-8');
echo bin2hex($utf16_string), "\n";
?>
以上例程会输出：
fffd
示例 #3 Characters which cannot be encoded
If the input string contains characters which cannot be represented
in toEncoding, they are replaced with a single
character. The default character to use depends on the encoding, and
can be controlled using the 'to_subst' option.
<?php
$utf8_string = "\xE2\x82\xAC"; // € (Euro Sign) does not exist in ISO 8859-1
// Default replacement in ISO 8859-1 is "\x1A" (Substitute)
$iso8859_1_string = UConverter::transcode($utf8_string, 'ISO-8859-1', 'UTF-8');
echo bin2hex($iso8859_1_string), "\n";
// Specify a replacement of '?' ("\x3F") instead
$iso8859_1_string = UConverter::transcode(
$utf8_string, 'ISO-8859-1', 'UTF-8', ['to_subst' => '?']
);
echo bin2hex($iso8859_1_string), "\n";
// Since ISO 8859-1 cannot map U+FFFD, invalid input is also replaced by to_subst
$invalid_utf8_string = "\xC3"; // incomplete multi-byte UTF-8 sequence
$iso8859_1_string = UConverter::transcode(
$invalid_utf8_string, 'ISO-8859-1', 'UTF-8', ['to_subst' => '?']
);
echo bin2hex($iso8859_1_string), "\n";
?>
以上例程会输出：
1a 3f 3f
