Splitting a string into groups, filtering strings

/**
* Split string into groups
* @param string $string: String
* @return return the broken array
*/
function Mbstringtoarray ($string) {
$string = $this->getchinaenglishnumstring ($string);
$array = Array ();
$strlen = Mb_strlen ($string);
while ($strlen) {
$array [] = Mb_substr ($string, 0,1, "UTF8");
$string = Mb_substr ($string, 1, $strlen, "UTF8");
$strlen = Mb_strlen ($string);
}
return $array;
}

/**
* Get string Chinese, numbers, letters, underline
* @param string $str: String
* @param string $charset: Encoding
* @return boolean|string
*/
function getchinaenglishnumstring ($str, $charset = ' utf8 ') {
if ($charset = = ' gb2312 ') {
if (!preg_match_all ("/^[". Chr (0XA1). " -". Chr (0xff)." a-za-z0-9_\-]+/", $str, $match)) {
return false;
}
Return implode (", $match [0]);
}
if ($charset = = ' UTF8 ') {
if (!preg_match_all ("/[\x{4e00}-\x{9fa5}a-za-z0-9_\-]+/u", $str, $match)) {
return false;
}
Return implode (", $match [0]);
}
return false;
}

Splitting a string into groups, filtering strings