[R] correlations between columns for each row

Rob Griffin robgriffin247 at hotmail.com
Tue Nov 15 21:38:26 CET 2011


Excellent, as.matrix() didn't work but switched it to as.numeric() around 
the definition of both variables in the function and it did work:

rF <- function(x, a, b) cor(as.numeric(x[a]), as.numeric(x[b]), use = 
"complete.obs")
maindata$rFcor<-apply(maindata,1,FUN=rF,a=174:213,b=214:253)

Thanks very much both of you!
Rob

-----Original Message----- 
From: R. Michael Weylandt <michael.weylandt at gmail.com>
Sent: Tuesday, November 15, 2011 9:28 PM
To: Rob Griffin
Cc: Joshua Wiley ; r-help at r-project.org
Subject: Re: [R] correlations between columns for each row

Is the whole thing a data frame? Then any multi-column subset is also a data 
frame. Try adding a as.matrix() wrapper  in the definition of rF.

Michael

On Nov 15, 2011, at 3:14 PM, "Rob Griffin" <robgriffin247 at hotmail.com> 
wrote:

> Error in cor(x[a], x[b], use = "complete.obs") : 'x' must be numeric
>
> This is strange, it works on your example (and you've understood what I'm 
> trying to do perfectly), but then when I use it on the original data it 
> comes up with the error above
> I've checked str() and the columns are all numeric
>
> ???
>
> -----Original Message----- From: Joshua Wiley
> Sent: Tuesday, November 15, 2011 7:14 PM
> To: robgriffin247
> Cc: r-help at r-project.org
> Subject: Re: [R] correlations between columns for each row
>
> Hi Rob,
>
> Here is one approach:
>
>
> ## define a function that does the calculations
> ## (the covariance of two vectors divided by the square root of
> ## the products of their variances is just a correlation)
> rF <- function(x, a, b) cor(x[a], x[b], use = "complete.obs")
>
> set.seed(1)
> bigdata <- matrix(rnorm(271 * 13890), ncol = 271)
>
> results <- apply(bigdata, 1, FUN = rF, a = 174:213, b = 214:253)
>
> ## combine
> bigdata <- cbind(bigdata, iecorr = results)
>
> Hope this helps,
>
> Josh
>
> On Tue, Nov 15, 2011 at 8:42 AM, robgriffin247
> <robgriffin247 at hotmail.com> wrote:
>> Just as an update on this problem:
>> I have managed to get the variance for the selected columns
>>
>> Now all I need is the covariance between these 2 selections -
>> the two target columns are and the aim is that a new column contain a
>> covariance value between these on each row:
>>
>> maindata[,c(174:213)] and maindata[,c(214:253]
>>
>> I've played around with all sorts of apply (and derivatives of apply) and 
>> in
>> various different setups so I think I'm close but I feel like I'm chasing 
>> my
>> tail here!
>>
>> --
>> View this message in context: 
>> http://r.789695.n4.nabble.com/correlations-between-columns-for-each-row-tp4039193p4073208.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide 
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>
>
> -- 
> Joshua Wiley
> Ph.D. Student, Health Psychology
> Programmer Analyst II, ATS Statistical Consulting Group
> University of California, Los Angeles
> https://joshuawiley.com/
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.



More information about the R-help mailing list