# Re: [R] applying cor.test to a (m, n) matrix

From: Yasir Kaheil <kaheil_at_gmail.com>
Date: Thu, 08 May 2008 23:23:37 -0700 (PDT)

interesting request..I'm looking forward to the replies All I could come up with is putting it in two lines.. pr<-array(0,c(dim(x),dim(x)));
for (i in 1:dim(x)) for (j in 1:dim(x)) pr[i,j]<-cor.test(x[,i],x[,j])\$p.val;

y

Monica Pisica wrote:
>
>
> Hi everybody,
>
> I would like to apply cor.test to a matrix with m rows and n columns and
> get the results in a list of matrices , one matrix for p.val, one for the
> statistic, one for the correlation and 2 for upper and lower confidence
> intervals, something analog with cor() applied to a matrix.
>
> I have done my own function to get a matrix of p.values and i suppose i
> can build similar functions for all the others. But i have used for loops
> and i wonder if there is any way to actually use one of the functions from
> the "apply" family to do this in a quicker way.
>
> Here is my little function:
>
> cor.pval <- function(x, method = c("pearson", "kendal", "spearman"),
> digit=8) {
> n <- dim(x)
> pval <- matrix(paste(rep("c", n*n), seq(1,n*n), sep = ""), n, n, byrow =
> T)
> for (i in 1:n) {
> for (j in 1:n){
> pval[i, j] <- cor.test(x[,i], x[,j], method = method)\$p.value
> }
> }
> pval <- matrix(round(as.numeric(pval),digit), n, n, byrow = T)
> rownames(pval) <- colnames(x)
> colnames(pval) <- colnames(x)
> return(pval)
> }
>
> Thanks for any input,
>
> Monica
>
>
>
>
>
>
>
> _________________________________________________________________
>
>
> esh_messenger_052008
> ______________________________________________
> R-help_at_r-project.org mailing list
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> and provide commented, minimal, self-contained, reproducible code.
>
>

Yasir H. Kaheil
Catchment Research Facility
The University of Western Ontario
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