public long rowsWithNa ( ) { if ( _rowsWithNa != - 1 ) return _rowsWithNa ; String x = String . format ( "(na.omit %s)" , _fr . _key ) ; Val res = Rapids . exec ( x ) ; Frame f = res . getFrame ( ) ; long cnt = _fr . numRows ( ) - f . numRows ( ) ; f . delete ( ) ; return ( _rowsWithNa = cnt ) ; }
count of rows with nas