[R] loop problem

[TEMPL Matthias]

Hello Frank

> Hi,
> Here is my problem. Say I have two matrices,
> 
> Matrix A:
> 
> a b c
> 4 5 2
> 3 2 1 
> 4 5 6 
> 
> Matrix B:
> d e f g h
> 3 4 5 2 1
> 2 3 7 8 6
> 8 5 1 3 4

Please produce a reproducable example, like

A <- matrix(rnorm(9),ncol=3)
B <- matrix(rnorm(15), ncol=5)


Here is just the loop for you:

n <- 0

z <- vector()  # or z <- 1:(dim(A)[2]+dim(B)[2])
for(i in 1:dim(A)[2]){
  for( j in 1:dim(B)[2] ){
    n <- n + 1
    z[n] <- cor(A[,i], B[,j])
  }
}

I hope this helps,
Matthias

> 
> I would like to correlate vector a of matrix A with with 
> vectors d,e,f,g,h of matrix "B" and save the p-values (or 
> some type of statistic) in a seperate result vector, say z. 
> Then, I would like to repeat this process for vector b and 
> vector c of matrix A. In the present example, vector z would 
> end up containg 15 elements. 
> I tried a few double loops, but was not successful in saving 
> the results in a vector. I was only able to print them with 
> the "print" or "cat" command, but could not turn the print or 
> cat results into an accessible object. 
> 
> Help would be appreciated.
> Thank you,
> Frank. 
> 
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> 
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