我想获取按站分组的系列列的均值，但按年份将其分开。
我的数据看起来像这样
+---------+------+-------+------+------+------+
| station | year | month | tmax | tmin | rain |
+---------+------+-------+------+------+------+
| A | 2006 | 1 | 15 | 15 | NA |
| A | 2006 | 2 | 25 | 16 | 4 |
| A | 2006 | 3 | 30 | 18 | 7 |
| A | 2006 | 4 | 40 | 18 | 5 |
| A | 2007 | 1 | 15 | 15 | 6 |
| A | 2007 | 2 | 25 | 16 | 8 |
| A | 2007 | 3 | 30 | 18 | 10 |
| A | 2007 | 4 | 40 | 18 | 3 |
| A | 2008 | 1 | 15 | 15 | 5 |
| A | 2008 | 2 | 25 | 16 | 8 |
| A | 2008 | 3 | 30 | 18 | 1 |
| A | 2008 | 4 | 40 | 18 | 3 |
| B | 2006 | 1 | 15 | 15 | NA |
| B | 2006 | 2 | 25 | 16 | 4 |
| B | 2006 | 3 | 30 | 18 | 7 |
| B | 2006 | 4 | 40 | 18 | 5 |
| B | 2007 | 1 | 15 | 15 | 6 |
| B | 2007 | 2 | 25 | 16 | |
| B | 2007 | 3 | 30 | 18 | |
| B | 2007 | 4 | 40 | 18 | |
| B | 2008 | | | | |
+---------+------+-------+------+------+------+
我已经尝试过了，但是我觉得我完全没有把握要点，并且没有得到想要的输出
t <- NewData %>% group_by(station) %>%
summarise_at(vars(-station, -year), funs(mean(., na.rm=TRUE)))
我想获得类似这样的输出
+---------+------+------+------+------+
| station | year | tmax | tmin | rain |
+---------+------+------+------+------+
| A | 2006 | 15 | 15 | NA |
| A | 2007 | 25 | 16 | 4 |
| A | 2008 | 30 | 18 | 7 |
| B | 2006 | 40 | 18 | 5 |
| B | 2007 | 15 | 15 | 6 |
| B | 2008 | 25 | 16 | 8 |
| C | 2006 | 30 | 18 | 10 |
| C | 2007 | 40 | 18 | 3 |
| C | 2008 | 15 | 15 | 5 |
+---------+------+------+------+------+
谢谢！