On Jul 22, 2009, at 3:18 PM, megh wrote:
Hi,
I have created a list object like that :
x = vector("list")
for (i in 1:5) x[[i]] = rnorm(2)
x
So now you have a list with 5 elements
Now I want to do two things :
1. for each i, I want to do following matrix calculation : t(x[[i]])
%*%
x[[i]] i.e. for each i, I want to get a 2x2 matrix
Why not use an object of class matrix?
x <- matrix(rnorm(10), nrow=5)
> t(x) %*% x
[,1] [,2]
[1,] 6.621608 -1.558713
[2,] -1.558713 1.555916
2. Next I want to get x[[1]] + x[[2]] +....
I did following : res=vector("list"); res = sapply(x, function(i)
t(x[[i]])
%*% x[[i]])
However above syntax is not giving desired result. Any suggestion
please?
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