Multibyte String 函数
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mb_convert_encoding

(PHP 4 >= 4.0.6, PHP 5)

mb_convert_encoding — Convert character encoding

说明

string mb_convert_encoding ( string $str , string $to_encoding [, mixed $from_encoding ] )

Converts the character encoding of string str to to_encoding from optionally from_encoding.

参数

str

The string being encoded.

to_encoding

The type of encoding that str is being converted to.

from_encoding

Is specified by character code names before conversion. It is either an array, or a comma separated enumerated list. If from_encoding is not specified, the internal encoding will be used.

See supported encodings.

返回值

The encoded string.

范例

Example #1 mb_convert_encoding() example

<?php
/* Convert internal character encoding to SJIS */
$str = mb_convert_encoding($str, "SJIS");

/* Convert EUC-JP to UTF-7 */
$str = mb_convert_encoding($str, "UTF-7", "EUC-JP");

/* Auto detect encoding from JIS, eucjp-win, sjis-win, then convert str to UCS-2LE */
$str = mb_convert_encoding($str, "UCS-2LE", "JIS, eucjp-win, sjis-win");

/* "auto" is expanded to "ASCII,JIS,UTF-8,EUC-JP,SJIS" */
$str = mb_convert_encoding($str, "EUC-JP", "auto");
?>

参见

Multibyte String 函数
在线手册：中文 英文
PHP手册
PHP手册 - N: Convert character encoding

用户评论:

qdb at kukmara dot ru (07-Nov-2011 03:44)

mb_substr and probably several other functions works faster in ucs-2 than in utf-8. and utf-16 works slower than utf-8. here is test, ucs-2 is near 50 times faster than utf-8, and utf-16 is near 6 times slower than utf-8 here:
<?php
header('Content-Type: text/html; charset=utf-8');
mb_internal_encoding('utf-8');

$s='укгез??ш?хз?х?шк2049??лдябчсячмииюсит.июб?рарэ'
.'лдэфв??у?й?уй??у034928348539857?шаыдларораш??рлоавы';
$s.=$s;
$s.=$s;
$s.=$s;
$s.=$s;
$s.=$s;
$s.=$s;
$s.=$s;

$t1=microtime(true);
$i=0;
while($i<mb_strlen($s)){
    $a=mb_substr($s,$i,2);
    $i+=2;
    if($i==10)echo$a.'. ';
    //echo$a.'. ';
}
echo$i.'. ';
echo(microtime(true)-$t1);

echo'<br>';
$s=mb_convert_encoding($s,'UCS-2','utf8');
mb_internal_encoding('UCS-2');
$t1=microtime(true);
$i=0;
while($i<mb_strlen($s)){
    $a=mb_substr($s,$i,2);
    $i+=2;
    if($i==10)echo mb_convert_encoding($a,'utf8','ucs2').'. ';
    //echo$a.'. ';
}
echo$i.'. ';
echo(microtime(true)-$t1);

echo'<br>';
$s=mb_convert_encoding($s,'utf-16','ucs-2');
mb_internal_encoding('utf-16');
$t1=microtime(true);
$i=0;
while($i<mb_strlen($s)){
    $a=mb_substr($s,$i,2);
    $i+=2;
    if($i==10)echo mb_convert_encoding($a,'utf8','utf-16').'. ';
    //echo$a.'. ';
}
echo$i.'. ';
echo(microtime(true)-$t1);

?>
output:
?х. 12416. 1.71738100052
?х. 12416. 0.0211279392242
?х. 12416. 11.2330229282

Alexanderdotbooneatmnsudotedu (09-Jun-2011 06:50)

I was having trouble parsing an Excel document to html, this seems to do the trick for character encoding.

<?php
function decode_characters($info)
{
    $info = mb_convert_encoding($info, "HTML-ENTITIES", "UTF-8");
    $info = preg_replace('~^(&([a-zA-Z0-9]);)~',htmlentities('${1}'),$info);
    return($info);
}
?>

alvaro at demogracia dot com (06-Apr-2011 11:37)

You can use the HTML-ENTITIES encoding to insert arbitrary Unicode characters, e.g. "U+25B6 (BLACK RIGHT-POINTING TRIANGLE)":

<?php
$triangle = mb_convert_encoding('&#x25B6;', 'UTF-8', 'HTML-ENTITIES');
?>

Be aware though that older PHP versions do not seem to support hexadecimal notation (&#x25B6;). In such case, use decimal notation (&#9654;):

<?php
$triangle = mb_convert_encoding('&#9654;', 'UTF-8', 'HTML-ENTITIES');
?>

gullevek at gullevek dot org (25-Aug-2010 08:27)

If you want to convert japanese to ISO-2022-JP it is highly recommended to use ISO-2022-JP-MS as the target encoding instead. This includes the extended character set and avoids ? in the text. For example the often used "1 in a circle" ① will be correctly converted then.

regrunge at hotmail dot it (14-May-2010 04:00)

I've been trying to find the charset of a norwegian (with a lot of ?, ?, ?) txt file written on a Mac, i've found it in this way:

<?php
$text = "A strange string to pass, maybe with some ?, ?, ? characters.";

foreach(mb_list_encodings() as $chr){
        echo mb_convert_encoding($text, 'UTF-8', $chr)." : ".$chr."<br>";   
 }
?>

The line that looks good, gives you the encoding it was written in.

Hope can help someone

Daniel Trebbien (23-Jul-2009 07:25)

Note that `mb_convert_encoding($val, 'HTML-ENTITIES')` does not escape '\'', '"', '<', '>', or '&'.

me at gsnedders dot com (18-Jun-2009 11:06)

It appears that when dealing with an unknown "from encoding" the function will both throw an E_WARNING and proceed to convert the string from ISO-8859-1 to the "to encoding".

alexandrefelipemuller at gmail dot com (18-Feb-2009 08:06)

I used this function insted mb_convert_encoding, because mbstring wasn't enabled at my comercial server. It only suports utf7, 8 e iso 8859-1:

<?php
function my_convert_encoding($string,$to,$from)
{
        // Convert string to ISO_8859-1
        if ($from == "UTF-8")
                $iso_string = utf8_decode($string);
        else
                if ($from == "UTF7-IMAP")
                        $iso_string = imap_utf7_decode($string);
                else
                        $iso_string = $string;

        // Convert ISO_8859-1 string to result coding
        if ($to == "UTF-8")
                return(utf8_encode($iso_string));
        else
                if ($to == "UTF7-IMAP")
                        return(imap_utf7_encode($iso_string));
                else
                        return($iso_string);
}
?>

chzhang at gmail dot com (05-Jan-2009 08:34)

instead of ini_set(), you can try this

mb_substitute_character("none");

francois at bonzon point com (11-Nov-2008 01:05)

aaron, to discard unsupported characters instead of printing a ?, you might as well simply set the configuration directive:

mbstring.substitute_character = "none"

in your php.ini. Be sure to include the quotes around none. Or at run-time with

<?php
ini_set('mbstring.substitute_character', "none");
?>

aaron at aarongough dot com (07-Nov-2008 04:24)

My solution below was slightly incorrect, so here is the correct version (I posted at the end of a long day, never a good idea!)

Again, this is a quick and dirty solution to stop mb_convert_encoding from filling your string with question marks whenever it encounters an illegal character for the target encoding.

<?php
function convert_to ( $source, $target_encoding )
    {
    // detect the character encoding of the incoming file
    $encoding = mb_detect_encoding( $source, "auto" );
      
    // escape all of the question marks so we can remove artifacts from
    // the unicode conversion process
    $target = str_replace( "?", "[question_mark]", $source );
      
    // convert the string to the target encoding
    $target = mb_convert_encoding( $target, $target_encoding, $encoding);
      
    // remove any question marks that have been introduced because of illegal characters
    $target = str_replace( "?", "", $target );
      
    // replace the token string "[question_mark]" with the symbol "?"
    $target = str_replace( "[question_mark]", "?", $target );
  
    return $target;
    }
?>

Hope this helps someone! (Admins should feel free to delete my previous, incorrect, post for clarity)
-A

Edward (16-Sep-2008 11:54)

If mb_convert_encoding doesn't work for you, and iconv gives you a headache, you might be interested in this free class I found. It can convert almost any charset to almost any other charset. I think it's wonderful and I wish I had found it earlier. It would have saved me tons of headache.

I use it as a fail-safe, in case mb_convert_encoding is not installed. Download it from http://mikolajj.republika.pl/

This is not my own library, so technically it's not spamming, right? ;)

Hope this helps.

StigC (13-Aug-2008 11:38)

For the php-noobs (like me) - working with flash and php.

Here's a simple snippet of code that worked great for me, getting php to show special Danish characters, from a Flash email form:

<?php
// Name Escape
$escName = mb_convert_encoding($_POST["Name"], "ISO-8859-1", "UTF-8");

// message escape
$escMessage = mb_convert_encoding($_POST["Message"], "ISO-8859-1", "UTF-8");

// Headers.. and so on...
?>

nospam at nihonbunka dot com (16-May-2008 02:51)

rodrigo at bb2 dot co dot jp wrote that inconv works better than mb_convert_encoding, I find that when converting from uft8 to shift_jis
$conv_str = mb_convert_encoding($str,$toCS,$fromCS);
works while
$conv_str = iconv($fromCS,$toCS.'//IGNORE',$str);
removes tildes from $str.

katzlbtjunk at hotmail dot com (25-Jan-2008 12:36)

Clean a string for use as filename by simply replacing all unwanted characters with underscore (ASCII converts to 7bit). It removes slightly more chars than necessary. Hope its useful.

$fileName = 'Test:!"$%&/()=?????ü<<';
echo strtr(mb_convert_encoding($fileName,'ASCII'),
    ' ,;:?*#!§$%&/(){}<>=`?|\\\'"',
    '____________________________');

rodrigo at bb2 dot co dot jp (15-Jan-2008 11:47)

For those who can?t use mb_convert_encoding() to convert from one charset to another as a metter of lower version of php, try iconv().

I had this problem converting to japanese charset:

$txt=mb_convert_encoding($txt,'SJIS',$this->encode);

And I could fix it by using this:

$txt = iconv('UTF-8', 'SJIS', $txt);

Maybe it?s helpfull for someone else! ;)

mightye at gmail dot com (13-Nov-2007 05:24)

To petruzanauticoyahoo?com!ar

If you don't specify a source encoding, then it assumes the internal (default) encoding.  ? is a multi-byte character whose bytes in your configuration default (often iso-8859-1) would actually mean ?±.  mb_convert_encoding() is upgrading those characters to their multi-byte equivalents within UTF-8.

Try this instead:
<?php
print mb_convert_encoding( "?", "UTF-8", "UTF-8" );
?>
Of course this function does no work (for the most part - it can actually be used to strip characters which are not valid for UTF-8).

volker at machon dot biz (25-Sep-2007 05:05)

Hey guys. For everybody who's looking for a function that is converting an iso-string to utf8 or an utf8-string to iso, here's your solution:

public function encodeToUtf8($string) {
     return mb_convert_encoding($string, "UTF-8", mb_detect_encoding($string, "UTF-8, ISO-8859-1, ISO-8859-15", true));
}

public function encodeToIso($string) {
     return mb_convert_encoding($string, "ISO-8859-1", mb_detect_encoding($string, "UTF-8, ISO-8859-1, ISO-8859-15", true));
}

For me these functions are working fine. Give it a try

aofg (22-Aug-2007 02:49)

When converting Japanese strings to ISO-2022-JP or JIS on PHP >= 5.2.1, you can use "ISO-2022-JP-MS" instead of them.
Kishu-Izon (platform dependent) characters are converted correctly with the encoding, as same as with eucJP-win or with SJIS-win.

David Hull (20-Dec-2006 06:52)

As an alternative to Johannes's suggestion for converting strings from other character sets to a 7bit representation while not just deleting latin diacritics, you might try this:

<?php
$text = iconv($from_enc, 'US-ASCII//TRANSLIT', $text);
?>

The only disadvantage is that it does not convert "?" to "ae", but it handles punctuation and other special characters better.
--
David

phpdoc at jeudi dot de (05-Sep-2006 02:46)

I\&#039;d like to share some code to convert latin diacritics to their
traditional 7bit representation, like, for example,

- &agrave;,&ccedil;,&eacute;,&icirc;,... to a,c,e,i,...
- &szlig; to ss
- &auml;,&Auml;,... to ae,Ae,...
- &euml;,... to e,...

(mb_convert \&quot;7bit\&quot; would simply delete any offending characters).

I might have missed on your country\&#039;s typographic
conventions--correct me then.
&lt;?php
/**
 * @args string $text line of encoded text
 *       string $from_enc (encoding type of $text, e.g. UTF-8, ISO-8859-1)
 *
 * @returns 7bit representation
 */
function to7bit($text,$from_enc) {
    $text = mb_convert_encoding($text,\&#039;HTML-ENTITIES\&#039;,$from_enc);
    $text = preg_replace(
        array(\&#039;/&szlig;/\&#039;,\&#039;/&amp;(..)lig;/\&#039;,
             \&#039;/&amp;([aouAOU])uml;/\&#039;,\&#039;/&amp;(.)[^;]*;/\&#039;),
        array(\&#039;ss\&#039;,\&quot;$1\&quot;,\&quot;$1\&quot;.\&#039;e\&#039;,\&quot;$1\&quot;),
        $text);
    return $text;
}  
?&gt;

Enjoy :-)
Johannes

==
[EDIT BY danbrown AT php DOT net: Author provided the following update on 27-FEB-2012.]
==

An addendum to my &quot;to7bit&quot; function referenced below in the notes.
The function is supposed to solve the problem that some languages require a different 7bit rendering of special (umlauted) characters for sorting or other applications. For example, the German &szlig; ligature is usually written &quot;ss&quot; in 7bit context. Dutch &yuml; is typically rendered &quot;ij&quot; (not &quot;y&quot;).

The original function works well with word (alphabet) character entities and I&#039;ve seen it used in many places. But non-word entities cause funny results:
E.g., &quot;&copy;&quot; is rendered as &quot;c&quot;, &quot;&shy;&quot; as &quot;s&quot; and &quot;&amp;rquo;&quot; as &quot;r&quot;.
The following version fixes this by converting non-alphanumeric characters (also chains thereof) to &#039;_&#039;.

&lt;?php
/**
 * @args string $text line of encoded text
 *       string $from_enc (encoding type of $text, e.g. UTF-8, ISO-8859-1)
 *
 * @returns 7bit representation
 */
function to7bit($text,$from_enc) {
    $text = preg_replace(/W+/,&#039;_&#039;,$text);
    $text = mb_convert_encoding($text,&#039;HTML-ENTITIES&#039;,$from_enc);
    $text = preg_replace(
        array(&#039;/&szlig;/&#039;,&#039;/&amp;(..)lig;/&#039;,
             &#039;/&amp;([aouAOU])uml;/&#039;,&#039;/&yuml;/&#039;,&#039;/&amp;(.)[^;]*;/&#039;),
        array(&#039;ss&#039;,&quot;$1&quot;,&quot;$1&quot;.&#039;e&#039;,&#039;ij&#039;,&quot;$1&quot;),
        $text);
    return $text;
} 
?&gt;

Enjoy again,
Johannes

mac.com@nemo (08-Jul-2006 03:38)

For those wanting to convert from $set to MacRoman, use iconv():

<?php

$string = iconv('UTF-8', 'macintosh', $string);

?>

('macintosh' is the IANA name for the MacRoman character set.)

eion at bigfoot dot com (21-Feb-2006 12:54)

many people below talk about using
<?php
    mb_convert_encode($s,'HTML-ENTITIES','UTF-8');
?>
to convert non-ascii code into html-readable stuff.  Due to my webserver being out of my control, I was unable to set the database character set, and whenever PHP made a copy of my $s variable that it had pulled out of the database, it would convert it to nasty latin1 automatically and not leave it in it's beautiful UTF-8 glory.

So [insert korean characters here] turned into ?????.

I found myself needing to pass by reference (which of course is deprecated/nonexistent in recent versions of PHP)
so instead of
<?php
    mb_convert_encode(&$s,'HTML-ENTITIES','UTF-8');
?>
which worked perfectly until I upgraded, so I had to use
<?php
    call_user_func_array('mb_convert_encoding', array(&$s,'HTML-ENTITIES','UTF-8'));
?>

Hope it helps someone else out

Tom Class (11-Nov-2005 03:35)

Why did you use the php html encode functions? mbstring has it's own Encoding which is (as far as I tested it) much more usefull:

HTML-ENTITIES

Example:

$text = mb_convert_encoding($text, 'HTML-ENTITIES', "UTF-8");

Stephan van der Feest (09-Sep-2005 12:47)

To add to the Flash conversion comment below, here's how I convert back from what I've stored in a database after converting from Flash HTML text field output, in order to load it back into a Flash HTML text field:

function htmltoflash($htmlstr)
{
  return str_replace("&lt;br /&gt;","\n",
    str_replace("<","&lt;",
      str_replace(">","&gt;",
        mb_convert_encoding(html_entity_decode($htmlstr),
        "UTF-8","ISO-8859-1"))));
}

Stephan van der Feest (09-Sep-2005 11:50)

Here's a tip for anyone using Flash and PHP for storing HTML output submitted from a Flash text field in a database or whatever.

Flash submits its HTML special characters in UTF-8, so you can use the following function to convert those into HTML entity characters:

function utf8html($utf8str)
{
  return htmlentities(mb_convert_encoding($utf8str,"ISO-8859-1","UTF-8"));
}

jamespilcher1 - hotmail (02-Feb-2004 03:55)

be careful when converting from iso-8859-1 to utf-8.

even if you explicitly specify the character encoding of a page as iso-8859-1(via headers and strict xml defs), windows 2000 will ignore that and interpret it as whatever character set it has natively installed.

for example, i wrote char #128 into a page, with char encoding iso-8859-1, and it displayed in internet explorer (& mozilla) as a euro symbol.

it should have displayed a box, denoting that char #128 is undefined in iso-8859-1. The problem was it was displaying in "Windows: western europe" (my native character set).

this led to confusion when i tried to convert this euro to UTF-8 via mb_convert_encoding() 

IE displays UTF-8 correctly- and because PHP correctly converted #128 into a box in UTF-8, IE would show a box.

so all i saw was mb_convert_encoding() converting a euro symbol into a box. It took me a long time to figure out what was going on.

lanka at eurocom dot od dot ua (07-Feb-2003 04:03)

Another sample of recoding without MultiByte enabling.
(Russian koi->win, if input in win-encoding already, function recode() returns unchanged string)

<?php
  // 0 - win
  // 1 - koi
  function detect_encoding($str) {
    $win = 0;
    $koi = 0;

    for($i=0; $i<strlen($str); $i++) {
      if( ord($str[$i]) >224 && ord($str[$i]) < 255) $win++;
      if( ord($str[$i]) >192 && ord($str[$i]) < 223) $koi++;
    }

    if( $win < $koi ) {
      return 1;
    } else return 0;

  }

  // recodes koi to win
  function koi_to_win($string) {

    $kw = array(128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183,  184, 185, 186, 187, 188, 189, 190, 191, 254, 224, 225, 246, 228, 229, 244, 227, 245, 232, 233, 234, 235, 236, 237, 238, 239, 255, 240, 241, 242, 243, 230, 226, 252, 251, 231, 248, 253, 249, 247, 250, 222, 192, 193, 214, 196, 197, 212, 195, 213, 200, 201, 202, 203, 204, 205, 206, 207, 223, 208, 209, 210, 211, 198, 194, 220, 219, 199, 216, 221, 217, 215, 218);
    $wk = array(128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183,  184, 185, 186, 187, 188, 189, 190, 191, 225, 226, 247, 231, 228, 229, 246, 250, 233, 234, 235, 236, 237, 238, 239, 240, 242,  243, 244, 245, 230, 232, 227, 254, 251, 253, 255, 249, 248, 252, 224, 241, 193, 194, 215, 199, 196, 197, 214, 218, 201, 202, 203, 204, 205, 206, 207, 208, 210, 211, 212, 213, 198, 200, 195, 222, 219, 221, 223, 217, 216, 220, 192, 209);

    $end = strlen($string);
    $pos = 0;
    do {
      $c = ord($string[$pos]);
      if ($c>128) {
        $string[$pos] = chr($kw[$c-128]);
      }

    } while (++$pos < $end);

    return $string;
  }

  function recode($str) {

    $enc = detect_encoding($str);
    if ($enc==1) {
      $str = koi_to_win($str);
    }

    return $str;
  }
?>