在PHP中将字符串拆分为Unicode字符数组的最佳方法是什么？

In PHP < 6, what is the best way to split a string into an array of Unicode characters? If the input is not necessarily UTF-8?

在PHP <6中，将字符串拆分为Unicode字符数组的最佳方法是什么？如果输入不一定是UTF-8？

I want to know whether the set of Unicode characters in an input string is a subset of another set of Unicode characters.

我想知道输入字符串中的Unicode字符集是否是另一组Unicode字符的子集。

Why not run straight for the mb_ family of functions, as the first couple of answers didn't?

为什么不直接运行mb_系列函数，因为前几个答案没有？

6 个解决方案

#1

You could use the 'u' modifier with PCRE regex ; see Pattern Modifiers (quoting) :

您可以将'u'修饰符与PCRE正则表达式一起使用;见模式修饰符（引用）：

u (PCRE8)

你（PCRE8）

This modifier turns on additional functionality of PCRE that is incompatible with Perl. Pattern strings are treated as UTF-8. This modifier is available from PHP 4.1.0 or greater on Unix and from PHP 4.2.3 on win32. UTF-8 validity of the pattern is checked since PHP 4.3.5.

此修饰符打开与Perl不兼容的PCRE的其他功能。模式字符串被视为UTF-8。这个修饰符可以在Unix上从PHP 4.1.0或更高版本获得，在win32上从PHP 4.2.3获得。自PHP 4.3.5起，检查模式的UTF-8有效性。

For instance, considering this code :

例如，考虑以下代码：

header('Content-type: text/html; charset=UTF-8');  // So the browser doesn't make our lives harder
$str = "abc 文字化け, efg";

$results = array();
preg_match_all('/./', $str, $results);
var_dump($results[0]);

You'll get an unusable result:

你会得到一个无法使用的结果：

array
  0 => string 'a' (length=1)
  1 => string 'b' (length=1)
  2 => string 'c' (length=1)
  3 => string ' ' (length=1)
  4 => string '�' (length=1)
  5 => string '�' (length=1)
  6 => string '�' (length=1)
  7 => string '�' (length=1)
  8 => string '�' (length=1)
  9 => string '�' (length=1)
  10 => string '�' (length=1)
  11 => string '�' (length=1)
  12 => string '�' (length=1)
  13 => string '�' (length=1)
  14 => string '�' (length=1)
  15 => string '�' (length=1)
  16 => string ',' (length=1)
  17 => string ' ' (length=1)
  18 => string 'e' (length=1)
  19 => string 'f' (length=1)
  20 => string 'g' (length=1)

But, with this code :

但是，使用此代码：

header('Content-type: text/html; charset=UTF-8');  // So the browser doesn't make our lives harder
$str = "abc 文字化け, efg";

$results = array();
preg_match_all('/./u', $str, $results);
var_dump($results[0]);

(Notice the 'u' at the end of the regex)

（请注意正则表达式末尾的'u'）

You get what you want :

你得到你想要的：

array
  0 => string 'a' (length=1)
  1 => string 'b' (length=1)
  2 => string 'c' (length=1)
  3 => string ' ' (length=1)
  4 => string '文' (length=3)
  5 => string '字' (length=3)
  6 => string '化' (length=3)
  7 => string 'け' (length=3)
  8 => string ',' (length=1)
  9 => string ' ' (length=1)
  10 => string 'e' (length=1)
  11 => string 'f' (length=1)
  12 => string 'g' (length=1)

Hope this helps :-)

希望这可以帮助：-）

#2

Slightly simpler than preg_match_all:

比preg_match_all稍微简单：

preg_split('//u', $str, -1, PREG_SPLIT_NO_EMPTY)

This gives you back a 1-dimensional array of characters. No need for a matches object.

这样可以返回一维的字符数组。不需要匹配对象。

#3

Try this:

尝试这个：

preg_match_all('/./u', $text, $array);

#4

If for some reason the regex way isn't enough for you. I once wrote the Zend_Locale_UTF8 which is abandoned but might be helping you if you decide to do it on your own.

如果由于某种原因，正则表达方式对你来说还不够。我曾经写过Zend_Locale_UTF8，但是如果您决定自己动手，可能会帮助您。

In particular have a look at the class Zend_Locale_UTF8_PHP5_String which reads in Unicode strings and to work with them splits them up into single chars(which may consist out of multiple bytes obviously).

特别是看看Zend_Locale_UTF8_PHP5_String类，它读取Unicode字符串并使用它们将它们分成单个字符（显然可能由多个字节组成）。

EDIT: I just relaized that ZF's svn-browser is down so I copied the important methods for convenience:

编辑：我只是重新说ZF的svn浏览器已关闭，所以为了方便我复制了重要的方法：

/**
 * Returns the UTF-8 code sequence as an array for any given $string.
 *
 * @access protected
 * @param string|integer $string
 * @return array
 */
protected function _decode( $string ) {

    $string     = (string) $string;
    $length     = strlen($string);
    $sequence   = array();

    for ( $i=0; $i<$length; ) {
        $bytes      = $this->_characterBytes($string, $i);
        $ord        = $this->_ord($string, $bytes, $i);

        if ( $ord !== false )
            $sequence[] = $ord;

        if ( $bytes === false )
            $i++;
        else
            $i  += $bytes;
    }

    return $sequence;

}

/**
 * Returns the UTF-8 code of a character.
 *
 * @see http://en.wikipedia.org/wiki/UTF-8#Description
 * @access protected
 * @param string $string
 * @param integer $bytes
 * @param integer $position
 * @return integer
 */
protected function _ord( &$string, $bytes = null, $pos=0 )
{
    if ( is_null($bytes) )
        $bytes = $this->_characterBytes($string);

    if ( strlen($string) >= $bytes ) {

        switch ( $bytes ) {
            case 1:
                return ord($string[$pos]);
                break;

            case 2:
                return  ( (ord($string[$pos])   & 0x1f) << 6 ) +
                        ( (ord($string[$pos+1]) & 0x3f) );
                break;

            case 3:
                return  ( (ord($string[$pos])   & 0xf)  << 12 ) + 
                        ( (ord($string[$pos+1]) & 0x3f) << 6 ) +
                        ( (ord($string[$pos+2]) & 0x3f) );
                break;

            case 4:
                return  ( (ord($string[$pos])   & 0x7)  << 18 ) + 
                        ( (ord($string[$pos+1]) & 0x3f) << 12 ) + 
                        ( (ord($string[$pos+1]) & 0x3f) << 6 ) +
                        ( (ord($string[$pos+2]) & 0x3f) );
                break;

            case 0:
            default:
                return false;
        }
    }

    return false;
}
/**
 * Returns the number of bytes of the $position-th character.
 *
 * @see http://en.wikipedia.org/wiki/UTF-8#Description
 * @access protected
 * @param string $string
 * @param integer $position
 */
protected function _characterBytes( &$string, $position = 0 ) {
    $char       = $string[$position];
    $charVal    = ord($char);

    if ( ($charVal & 0x80) === 0 )
        return 1;

    elseif ( ($charVal & 0xe0) === 0xc0 )
        return 2;

    elseif ( ($charVal & 0xf0) === 0xe0 )
        return 3;

    elseif ( ($charVal & 0xf8) === 0xf0)
        return 4;
    /*
    elseif ( ($charVal & 0xfe) === 0xf8 )
        return 5;
    */

    return false;
}

#5

I was able to write a solution using mb_*, including a trip to UTF-16 and back in a probably silly attempt to speed up string indexing:

我能够使用mb_ *编写一个解决方案，包括一次UTF-16之旅，并回到可能是愚蠢的尝试来加速字符串索引：

$japanese2 = mb_convert_encoding($japanese, "UTF-16", "UTF-8");
$length = mb_strlen($japanese2, "UTF-16");
for($i=0; $i<$length; $i++) {
    $char = mb_substr($japanese2, $i, 1, "UTF-16");
    $utf8 = mb_convert_encoding($char, "UTF-8", "UTF-16");
    print $utf8 . "\n";
}

I had better luck avoiding mb_internal_encoding and just specifying everything at each mb_* call. I'm sure I'll wind up using the preg solution.

我有更好的运气避免mb_internal_encoding，只是在每次mb_ *调用时指定所有内容。我相信我最终会使用preg解决方案。

#6

the best way for split with length: I just changed laravel str_limit() function:

分裂长度的最佳方法：我刚改变了laravel str_limit（）函数：

    public static function split_text($text, $limit = 100, $end = '')
{
    $width=mb_strwidth($text, 'UTF-8');
    if ($width <= $limit) {
        return $text;
    }
    $res=[];
    for($i=0;$i<=$width;$i=$i+$limit){
        $res[]=rtrim(mb_strimwidth($text, $i, $limit, '', 'UTF-8')).$end;
    }
     return $res;
}

#1