/// <summary> /// Selects a set of columns. This is a variant of `select` that can only select /// existing columns using column names (i.e. cannot construct expressions). /// /// df.Select("colA", "colB") /// /// </summary> /// <param name="firstColumnName">first column name - required</param> /// <param name="otherColumnNames">other column names - optional</param> /// <returns></returns> public DataFrame Select(string firstColumnName, params string[] otherColumnNames) { return(new DataFrame(dataFrameProxy.Select(firstColumnName, otherColumnNames), sparkContext)); }