我希望通过我现有的当前数据帧创建下表。我当前的数据帧如下
ID = c(rep("A",3), rep("B",5), rep("C",4))
NRT = c(3,3,4,5,5,3,3,4,3,3,5,5)
df = as.data.frame(cbind(ID,NRT))
| ID | NRT |
|---|---|
| A | 3 |
| A | 3 |
| A | 4 |
| B | 5 |
| B | 5 |
| B | 3 |
| B | 3 |
| B | 4 |
| C | 3 |
| C | 3 |
| C | 5 |
| C | 5 |
如果您考虑使用data.table而不是data.frame(注意data.table继承自data.frame(，这是最容易实现的
library(data.table)
ID = c(rep("A",3), rep("B",5), rep("C",4))
NRT = c(3,3,4,5,5,3,3,4,3,3,5,5)
df = as.data.frame(cbind(ID,NRT))
dt <- as.data.table(df)
dt[, list("NRT (Average)" = mean(NRT)), by = ID]
ID NRT (Average)
1: A 3.333333
2: B 4.000000
3: C 4.000000
如果你想在发布时准确地打印表格，你可以执行以下
library(data.table)
dt <- data.table(ID = c(rep("A",3), rep("B",5), rep("C",4)), NRT = c(3,3,4,5,5,3,3,4,3,3,5,5))
dt[, "NRT(Average)" := paste0(mean(NRT), " (average for NRT for ", ID, ")"), by = ID]
dt[, .SD[1], by = ID][, c(1, 3)]
ID NRT(Average)
1: A 3.33333333333333 (average for NRT for A)
2: B 4 (average for NRT for B)
3: C 4 (average for NRT for C)