如何使用此值填充数组（for 循环或 lapply 函数）？

Question

I have this values (simplify example):

a  #class numeric
 [1] 1 5 7 6 9

and this array:

res.tot <- array(NA,dim=c(2,1,5))

I need to fill the array res.tot with a values, in this way:

[[1]]
     [1]
[1] 1
[2] 1

[[2]]
     [1]
[1] 5
[2] 5

...
[[5]]
     [1]
[1] 9
[2] 9

in the array res.tot each value of a is repeated 2 times, and each repeated a value occupay a different z dimension. I tried with for loop in this way:

for (i in 1:length(a)){
  res.1 <- data.frame(rep(a[i],2))
  res.tot[,,i] <- res.1
  }

R tell me:

Error in res.tot.1[, , i] <- res.1 : incorrect number of subscripts

How can do it with for loop or lapply function?

Answer 1

Here is a brute force solution:

> a <- c(1,5,7,6,9)
> res.tot <- array(NA,dim=c(2,1,5))
> for (i in 1:(dim(res.tot)[1])) {
+   for (j in 1:(dim(res.tot)[2])) {
+     for (k in 1:(dim(res.tot)[3])) {
+       res.tot[i,j,k] <- a[k]
+     }
+   }
+ }
> res.tot
, , 1

     [,1]
[1,]    1
[2,]    1

, , 2

     [,1]
[1,]    5
[2,]    5

, , 3

     [,1]
[1,]    7
[2,]    7

, , 4

     [,1]
[1,]    6
[2,]    6

, , 5

     [,1]
[1,]    9
[2,]    9

and here is a one-liner solution:

> res.tot[] <- rep(a,each=2)
> res.tot
, , 1

     [,1]
[1,]    1
[2,]    1

, , 2

     [,1]
[1,]    5
[2,]    5

, , 3

     [,1]
[1,]    7
[2,]    7

, , 4

     [,1]
[1,]    6
[2,]    6

, , 5

     [,1]
[1,]    9
[2,]    9