PHP通用字符串截取函数

/** * 字符串截取通用函数 * @param  string  $str     要截取的字符串 * @param  integer $start   截取开始位置 * @param  integer  $length  截取长度 * @param  string  $charset 字符串编码格式 * @param  boolean $suffix  是否显示省略符号 * @return string           截取后的字符串 */function msubstr($str, $start = 0, $length, $charset = "utf-8", $suffix = false) {     if (function_exists("mb_substr")) {         if ($suffix)             return mb_substr($str, $start, $length, $charset) . "...";         else             return mb_substr($str, $start, $length, $charset);     } elseif (function_exists('iconv_substr')) {         if ($suffix)             return iconv_substr($str, $start, $length, $charset) . "...";         else             return iconv_substr($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; }echo msubstr('测试PHP字符串截取', 2, 5, 'utf-8', true);//结果：PHP字符...