[R] correlations between columns for each row

[R. Michael Weylandt <michael.weylandt@gmail.com>]

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
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>> 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.