我不明白为什么聚合函数生成的数据框的列名不能正确重命名？
我使用聚合函数按组进行一些汇总统计。在下文中，我提出了一个可重复的例子。
> data <- read.table(header=T, text='
+ subject sex condition before after change
+ 1 F placebo 10.1 6.9 -3.2
+ 2 F placebo 6.3 4.2 -2.1
+ 3 M aspirin 12.4 6.3 -6.1
+ 4 F placebo 8.1 6.1 -2.0
+ 5 M aspirin 15.2 9.9 -5.3
+ 6 F aspirin 10.9 7.0 -3.9
+ 7 F aspirin 11.6 8.5 -3.1
+ 8 M aspirin 9.5 3.0 -6.5
+ 9 F placebo 11.5 9.0 -2.5
+ 10 M placebo 11.9 11.0 -0.9
+ 11 F aspirin 11.4 8.0 -3.4
+ 12 M aspirin 10.0 4.4 -5.6
+ 13 M aspirin 12.5 5.4 -7.1
+ 14 M placebo 10.6 10.6 0.0
+ 15 M aspirin 9.1 4.3 -4.8
+ 16 F placebo 12.1 10.2 -1.9
+ 17 F placebo 11.0 8.8 -2.2
+ 18 F placebo 11.9 10.2 -1.7
+ 19 M aspirin 9.1 3.6 -5.5
+ 20 M placebo 13.5 12.4 -1.1
+ 21 M aspirin 12.0 7.5 -4.5
+ 22 F placebo 9.1 7.6 -1.5
+ 23 M placebo 9.9 8.0 -1.9
+ 24 F placebo 7.6 5.2 -2.4
+ 25 F placebo 11.8 9.7 -2.1
+ 26 F placebo 11.8 10.7 -1.1
+ 27 F aspirin 10.1 7.9 -2.2
+ 28 M aspirin 11.6 8.3 -3.3
+ 29 F aspirin 11.3 6.8 -4.5
+ 30 F placebo 10.3 8.3 -2.0
+ ')
>
> summary.function <- function(x){c(mean(abs(x)),mean(x),min(x),max(x))}
> data.summary <- aggregate(data=data,change~condition+sex,FUN=summary.function)
> data.summary
condition sex change.1 change.2 change.3 change.4
1 aspirin F 3.420000 -3.420000 -4.500000 -2.200000
2 placebo F 2.058333 -2.058333 -3.200000 -1.100000
3 aspirin M 5.411111 -5.411111 -7.100000 -3.300000
4 placebo M 0.975000 -0.975000 -1.900000 0.000000
> colnames(data.summary) <- c("condition","sex","absmean","mean","min","max")
Error in `colnames<-`(`*tmp*`, value = c("condition", "sex", "absmean", : 'names' attribute [6] must be the same length as the vector [3]
colnames()函数获取错误的列名：
> colnames(data.summary)
[1] "condition" "sex" "change"
有人能帮助我吗？
编辑： 在尝试其他软件包而不是在r基础之后，它也适用于
library(doBy)
data.summary <- summaryBy(change ~ sex + condition, data=data, FUN=summary.function) colnames(data.summary) <- c("condition","sex","absmean","mean","min","max")