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

From: Dimitris Rizopoulos <dimitris.rizopoulos_at_med.kuleuven.be>
Date: Fri, 09 May 2008 09:12:28 +0200

have a look also at function rcor.test() from package ltm.

Best,
Dimitris

Dimitris Rizopoulos
Biostatistical Centre
School of Public Health
Catholic University of Leuven

```Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
http://www.student.kuleuven.be/~m0390867/dimitris.htm

```

>
> 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)[2]
> 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
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