PHP字元截取函數，相容各類gbk,utf-8編碼

在PHP中字元截取函數substr只能截取全英文才不會出現亂碼如果裡面有中文肯定是無法截取的，下面小編來給大家介紹兩個相容各類gbk,utf-8編碼字串截取函數

例1

function CsubStrPro($str, $start, $length, $charset = "utf-8", $suffix = false){    if (function_exists ( "mb_substr" ))        return mb_substr ( $str, $start, $length, $charset );    $re ['utf-8'] = "/[x01-x7f]|[xc2-xdf][x80-xbf]|[xe0-xef][x80-xbf]{2}|[xf0-xff][x80-xbf]{3}/";    $re ['gb2312'] = "/[x01-x7f]|[xb0-xf7][xa0-xfe]/";    $re ['gbk'] = "/[x01-x7f]|[x81-xfe][x40-xfe]/";    $re ['big5'] = "/[x01-x7f]|[x81-xfe]([x40-x7e]|xa1-xfe])/";    preg_match_all ( $re [$charset], $str, $match );    $slice = join ( "", array_slice ( $match [0], $start, $length ) );    if ($suffix)        return $slice . "…";    return $slice;}

例2

function subString_UTF8($str, $start, $lenth)    {        $len = strlen($str);        $r = array();        $n = 0;        $m = 0;        for($i = 0; $i < $len; $i++) {            $x = substr($str, $i, 1);            $a  = base_convert(ord($x), 10, 2);            $a = substr('00000000'.$a, -8);            if ($n < $start){                if (substr($a, 0, 1) == 0) {                }elseif (substr($a, 0, 3) == 110) {                    $i += 1;                }elseif (substr($a, 0, 4) == 1110) {                    $i += 2;                }                $n++;            }else{                if (substr($a, 0, 1) == 0) {                    $r[ ] = substr($str, $i, 1);                }elseif (substr($a, 0, 3) == 110) {                    $r[ ] = substr($str, $i, 2);                    $i += 1;                }elseif (substr($a, 0, 4) == 1110) {                    $r[ ] = substr($str, $i, 3);                    $i += 2;                }else{                    $r[ ] = '';                }                if (++$m >= $lenth){                    break;                }            }        }        return $r;    } // End subString_UTF8;}// End String

#由於此函數返回的是一個數組，因此要配合join函數來顯示字串:例2

#join('',subString_UTF8($str, $start, $lenth));

#在頁面顯示的時候還可以在此語句後面連一個"..."

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