使用标题作为矩阵的行和列将数据集转换为矩阵

Question

我有一个数据集（显示的只是一个快照），我需要创建一个矩阵，其中处理为行，年份为列。矩阵内部需要包含Y列的均值和方差。

Y<-c(0,1,1,1,0,0,0,2,0,2)
Treatment<-c(0,0,0,0,1,1,1,1,1,1)
Year<-c(1,2,3,4,5,1,2,3,4,5)
dat<-as.data.frame(cbind(Y,Treatment,Year))
print(dat)

      Y Treatment Year
1     0         0    1
2     1         0    2
3     1         0    3
4     1         0    4
5     0         1    5
6     0         1    1
7     0         1    2
8     2         1    3
9     0         1    4
10    2         1    5

我希望我的矩阵能够显示Y列的均值和方差。

Answer 1

我认为你正在寻找类似的东西：

library(reshape2)
as.matrix(dcast(Treatment ~ Year, data = df, value.var = "Y", fun.aggregate = mean))
     Treatment 1 2 3 4   5
[1,]         0 0 1 1 1 NaN
[2,]         1 0 0 2 0   1

Answer 2

这是你在找什么？

Y<-c(0,1,1,1,0,0,0,2,0,2)
Treatment<-c(0,0,0,0,1,1,1,1,1,1)
Year<-c(1,2,3,4,5,1,2,3,4,5)
dat<-cbind(Y,Treatment,Year)
meanY<-mean(Y)
varY<-var(y)
dat1<-cbind(dat,meanY,varY)
print(dat1)
     Y Treatment Year meanY     varY
 [1,] 0         0    1   0.7 19.09091
 [2,] 1         0    2   0.7 19.09091
 [3,] 1         0    3   0.7 19.09091
 [4,] 1         0    4   0.7 19.09091
 [5,] 0         1    5   0.7 19.09091
 [6,] 0         1    1   0.7 19.09091
 [7,] 0         1    2   0.7 19.09091
 [8,] 2         1    3   0.7 19.09091
 [9,] 0         1    4   0.7 19.09091
[10,] 2         1    5   0.7 19.09091

如果计算该值并将其作为列添加到矩阵或数据框中，则R将扩展列的长度。