# [R] matrix merging question

arun smartpink111 at yahoo.com
Tue Feb 25 22:14:47 CET 2014

```Hi,
Sorry, a typo:

res1[rownames(mat1),] <- res[rownames(mat1),] + mat1
###should be:

res1[rownames(mat1),] <- res1[rownames(mat1),] + mat1

A.K.

On Tuesday, February 25, 2014 4:03 PM, arun <smartpink111 at yahoo.com> wrote:
HI Elio,
Not sure whether this helps:
length(list.files(pattern=".txt"))
#[1] 22
sapply(lst1,dim)
sapply(lst1,function(x) all(apply(rbind(colnames(x),rownames(x)),2,function(y) y[1]==y[2])))
#[1] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
#[16] TRUE TRUE TRUE TRUE TRUE TRUE TRUE
lst2 <- lapply(lst1,as.matrix)
uNrownames <- unique(as.vector(sapply(lst2,rownames)))
res1 <- matrix(0,nrow=length(uNrownames), ncol=ncol(lst2[[1]]), dimnames=list(uNrownames,NULL))

for(i in seq_along(lst2)){
mat1 <- lst2[[i]]
res1[rownames(mat1),] <- res[rownames(mat1),] + mat1
res1
}

dim(res1)
#[1] 90 90

A.K.

On Tuesday, February 25, 2014 2:52 PM, Elio Shijaku <selius at gmail.com> wrote:

Hi Arun,

I wanted to ask you again on the issue of merging several matrices. I tried to look through R-related pages on how to merge several symmetric matrices of same dimension (90x90) but with row names that need to be matched, but I didn't find any solution. What I found concerned the merging of two matrices which are not symmetric and that is not my case.

Can you help me with any code?

Attached are the files (in tab delimited text and/ Excel) that need to be merged.

What I want is a 90x90 final matrix that is the sum (aggregate) of all 22 matrices and that matches each variable.

I would appreciate your help if possible.

Best,

Elio

```