poszerzenia dataframe uzyskać miesięczne sumy dochodów wszystkich unikalnych wartościach catogorical kolumn w R
mam df, która ma dane jak poniżej: sub = c("X001","X002", "X001","X003","X002","X001","X001","X003","X002","X003","X003","X002")
month = c("201506", "201507", "201506","201507","201507","201508", "20