重写PHP的explode办法

function rexplode($delimiter, $str){
$d_len = strlen($delimiter);
$arr = array();
$i = $pos = 0;
while (false !== ($pos = stripos($str.$delimiter, $delimiter, $pos)) ) {
$arr[] = mb_substr($str, $i, $pos-$i);
$i = $pos + $d_len;
$pos += $d_len;
}
return array_filter($arr);
}