将数组转换为矩阵R

Question

我有一个数组，其中包括两个熟练变量（theta0，theta1）在一个项目上（是，否），称为“comp”。这需要转换为一个矩阵。有什么方法可以将底部的矩阵转换成矩阵吗？

我的数组是这样的：

>priCPT.i6 

, , comp = Yes 

theta1 
theta0  Low  Med  High 
    Low 0.8377206 0.6760511 0.4576021 
    Med 0.6760511 0.4576021 0.2543239 
    High 0.4576021 0.2543239 0.1211734 

, , comp = No 

    theta1 
theta0  Low  Med  High 
    Low 0.1622794 0.3239489 0.5423979 
    Med 0.3239489 0.5423979 0.7456761 
    High 0.5423979 0.7456761 0.8788266 

attr(,"class") 
[1] "CPA" "array" 

我很抱歉，我不能生产的东西，你可以玩。我在寻找的东西，如：

theta0 theta1 Yes  No 
Low  Low  0.8377206 0.1622794 
Low  Med  ..   .. 
Low  High  ..   .. 
Med  Low  ..   .. 
Med  Med  ..   .. 
Med  High  ..   .. 
High  Low  ..   .. 
High  Med  ..   .. 
High  High  ..   .. 

问候......

Answer 1

您可以轻松地在第三保证金扁平化矩阵获取值的列：

z1 <- apply(priCPT.i6, 3L, c) 
## we can also simply use `matrix`; but remember to set `dimnames` 
## otherwise we lose dimnames 
## z1 <- matrix(priCPT.i6, ncol = 2L, 
##    dimnames = list(NULL, dimnames(priCPT.i6)[[3]])) 

你需要的是什么剩下的就是追加“dimnames”列：

z2 <- expand.grid(dimnames(priCPT.i6)[1:2]) 

现在你可以将它们合并成一个数据帧（你defin itely需要比基体中的数据帧，因为z1列通过是数字而z2列字符）：使用reshape2将

data.frame(z2, z1) 

---

重现的实例

x <- array(1:18, dim = c(3L, 3L, 2L), dimnames = list(
      c("Low", "Medium", "High"), c("Low", "Medium", "High"), c("Yes", "No"))) 

#, , Yes 
# 
#  Low Medium High 
#Low  1  4 7 
#Medium 2  5 8 
#High  3  6 9 
# 
#, , No 
# 
#  Low Medium High 
#Low  10  13 16 
#Medium 11  14 17 
#High 12  15 18 

z1 <- apply(x, 3L, c) 
## z1 <- matrix(x, ncol = 2L, dimnames = list(NULL, dimnames(x)[[3]])) 
z2 <- expand.grid(dimnames(x)[1:2]) 
data.frame(z2, z1) 

# Var1 Var2 Yes No 
#1 Low Low 1 10 
#2 Medium Low 2 11 
#3 High Low 3 12 
#4 Low Medium 4 13 
#5 Medium Medium 5 14 
#6 High Medium 6 15 
#7 Low High 7 16 
#8 Medium High 8 17 
#9 High High 9 18 

Answer 2

一种替代be

x <- array(1:18, dim = c(3L, 3L, 2L), dimnames = list(
      c("Low", "Medium", "High"), 
      c("Low", "Medium", "High"), 
      c("Yes", "No"))) 

library(reshape2) 
df <- dcast(melt(x), Var1+Var2~Var3) 
df 

    Var1 Var2 Yes No 
1 Low Low 1 10 
2 Low Medium 4 13 
3 Low High 7 16 
4 Medium Low 2 11 
5 Medium Medium 5 14 
6 Medium High 8 17 
7 High Low 3 12 
8 High Medium 6 15 
9 High High 9 18