(PHP 5 >= 5.5.0, PHP 7, PHP 8, PECL >= 3.0.0a1)
UConverter::transcode — Convert a string from one character encoding to another
public static UConverter::transcode( string $str, string $toEncoding, string $fromEncoding, ?array $options = null ): string|false
Converts str from fromEncoding to toEncoding.
strThe string to be converted.
toEncodingThe desired encoding of the result.
fromEncoding The current encoding used to interpret str.
optionsAn 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 or false on failure.
Example #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"; ?>
The above example will output:
005a006f00eb 5a6fc3ab
Example #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"; ?>
The above example will output:
fffd
Example #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";
?> The above example will output:
1a 3f 3f
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https://www.php.net/manual/en/uconverter.transcode.php