public function tail(int $n = 10) : self
    {
        return self::quick(array_slice($this->samples, -$n));
    }
public function tail(int $n = 10) : self
    {
        return self::quick(array_slice($this->samples, -$n));
    }
public function tail ( int $ n = 10 ) : self { return self :: quick ( array_slice ( $ this -> samples , - $ n ) ) ; }
Return a dataset containing only the last n samples.

@param int $n
@return self
Return a dataset containing only the last n samples .