php字符串标点等字符截取不乱吗 封装方法

方法一：

/**
  +----------------------------------------------------------
 * 功能：字符串截取指定长度
 * leo.li hengqin2008@qq.com
  +----------------------------------------------------------
 * @param string    $string      待截取的字符串
 * @param int       $len         截取的长度
 * @param int       $start       从第几个字符開始截取
 * @param boolean   $suffix      是否在截取后的字符串后跟上省略号
  +----------------------------------------------------------
 * @return string               返回截取后的字符串
  +----------------------------------------------------------
 */
function cutStr($str, $len = 100, $start = 0, $suffix = 1) {
    $str = strip_tags(trim(strip_tags($str)));
    $str = str_replace(array(" ", " "), "", $str);
    $strlen = mb_strlen($str);
    while ($strlen) {
        $array[] = mb_substr($str, 0, 1, "utf8");
        $str = mb_substr($str, 1, $strlen, "utf8");
        $strlen = mb_strlen($str);
    }
    $end = $len + $start;
    $str = '';
    for ($i = $start; $i < $end; $i++) {
        $str.=$array[$i];
    }
    return count($array) > $len ? ($suffix == 1 ? $str . "&hellip;" : $str) : $str;
}

方法二：

header("Content-type:text/html; charset=utf8");
function cut_str($string, $sublen, $start = 0, $code = 'UTF-8') 
{ 
if($code == 'UTF-8') 
{ 
$pa ="/[x01-x7f]|[xc2-xdf][x80-xbf]|xe0[xa0-xbf][x80-xbf]|[xe1-xef][x80-xbf][x80-xbf]|xf0[x90-xbf][x80-xbf][x80-xbf]|[xf1-xf7][x80-xbf][x80-xbf][x80-xbf]/"; 
preg_match_all($pa, $string, $t_string); if(count($t_string[0]) - $start > $sublen) return join('', array_slice($t_string[0], $start, $sublen)); 
return join('', array_slice($t_string[0], $start, $sublen)); 
} 
else 
{ 
$start = $start*2; 
$sublen = $sublen*2; 
$strlen = strlen($string); 
$tmpstr = ''; for($i=0; $i<$strlen; $i++) 
{ 
if($i>=$start && $i<($start+$sublen)) 
{ 
if(ord(substr($string, $i, 1))>129) 
{ 
$tmpstr.= substr($string, $i, 2); 
} 
else 
{ 
$tmpstr.= substr($string, $i, 1); 
} 
} 
if(ord(substr($string, $i, 1))>129) $i++; 
} 
if(strlen($tmpstr)<$strlen ) $tmpstr.= ""; 
return $tmpstr; 
} 
} 


$str="我slskjd!fl是总那地方拉伸款到即发";

echo cut_str($str, 8, 5);