R分组多列并为它们指定行

Question

对于“nycflights13”包中的“飞机”数据，我有以下任务：

对于每个发动机及其制造商，确定生产年份：最早（最小），中等和最新（最多）。

我一直在尝试使用 table() 或 tapply() 来解决这个问题，但找不到解决方案。有什么建议吗？？

library(nycflights13)
data(planes)
head(planes)
  tailnum  year type                    manufacturer     model     engines seats speed engine   
  <chr>   <int> <chr>                   <chr>            <chr>       <int> <int> <int> <chr>    
1 N10156   2004 Fixed wing multi engine EMBRAER          EMB-145XR       2    55    NA Turbo-fan
2 N102UW   1998 Fixed wing multi engine AIRBUS INDUSTRIE A320-214        2   182    NA Turbo-fan
3 N103US   1999 Fixed wing multi engine AIRBUS INDUSTRIE A320-214        2   182    NA Turbo-fan
4 N104UW   1999 Fixed wing multi engine AIRBUS INDUSTRIE A320-214        2   182    NA Turbo-fan
5 N10575   2002 Fixed wing multi engine EMBRAER          EMB-145LR       2    55    NA Turbo-fan
6 N105UW   1999 Fixed wing multi engine AIRBUS INDUSTRIE A320-214        2   182    NA Turbo-fan

Answer 1

medium 是指获得中位数吗？你可以试试这个 -

library(dplyr)

planes %>%
  group_by(engines, manufacturer) %>%
  summarise(min = min(year, na.rm = TRUE), 
            medium = median(year, na.rm = TRUE), 
            max = max(year, na.rm = TRUE))

在基础 R 中使用 aggregate -

aggregate(year~engines + manufacturer, planes, function(x) 
  c(min = min(x, na.rm = TRUE), medium = median(x, na.rm = TRUE), 
    max = max(x, na.rm = TRUE)))

R分组多列并为它们指定行

R grouping multiple columns and designating rows for them

grouping

r