[R] [FORGED] filter correlation data

Rolf Turner r.turner at auckland.ac.nz
Tue Jan 31 23:47:12 CET 2017

On 01/02/17 10:34, Elham - via R-help wrote:

> hello everybody,I have a very very huge table in R from calculating
> correlation,how can I filter it per spearman correlation and p-value
> before export it,I mean what is the function that I use?I want to
> select the pairs for value (r), , greater than 0.9 (directly
> correlated) and less than -0.9 (inversely corerlated), and a p-value
> < 0.001
> I should say that I transformed the big matrix in a table by
> library(reshape).

(a) In this instance it doesn't really matter, but *PLEASE* stop posting 
in HTML.

(b) It's not at all clear what the structure of your (table? matrix? 
data frame) is.  Please learn to be precise and explicit, otherwise it 
is difficult-to-impossible to provide useful advice.  (I.e. don't expect 
us to be mind-readers.)

Let us suppose (for the sake of saying *something* that might be 
helpful) that your correlations and p-values are stored in a data frame 
"X" as columns named "r" and "pval".

Then assign

ok <- with(X, (r < -0.9 | r > 0.9) & pval < 0.001)
Y  <- X[ok,]

Then export Y.

Really, if you are going to use R you should learn something about R.


Rolf Turner

P.S.  Note that your p-value < 0.001 condition is redundant for any 
sample size greater than or equal to 7.

R. T.

Technical Editor ANZJS
Department of Statistics
University of Auckland
Phone: +64-9-373-7599 ext. 88276

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