public function bottom($num)
    {
        $count = $this->countData();
        $result = array();
        $start = ($count>$num)?$count-$num:0;
        for ($i=$start;$i<$count;$i++) {
            array_push($result, $this->rows[$i]);
        }
        return new DataStore($result, $this->metaData);
    }
public function bottom($num)
    {
        $count = $this->countData();
        $result = array();
        $start = ($count>$num)?$count-$num:0;
        for ($i=$start;$i<$count;$i++) {
            array_push($result, $this->rows[$i]);
        }
        return new DataStore($result, $this->metaData);
    }
public function bottom ( $ num ) { $ count = $ this -> countData ( ) ; $ result = array ( ) ; $ start = ( $ count > $ num ) ? $ count - $ num : 0 ; for ( $ i = $ start ; $ i < $ count ; $ i ++ ) { array_push ( $ result , $ this -> rows [ $ i ] ) ; } return new DataStore ( $ result , $ this -> metaData ) ; }
Return bottom rows of dataset

@param float $num Number of rows you want to return

@return DataStore New datastore containing result.
Return bottom rows of dataset