[R] By() with method = spearman

[Doran, Harold]

Thanks, Chuck. Seems odd though, doesn't it? There must be something
with my data set. But, I don't have any clue what it might be since I
can compute pearson using by() and I can subset and actually compute
spearman using just cor() 

> -----Original Message-----
> From: Chuck Cleland [mailto:ccleland at optonline.net] 
> Sent: Wednesday, September 19, 2007 12:14 PM
> To: Doran, Harold
> Cc: r-help at r-project.org
> Subject: Re: [R] By() with method = spearman
> 
> Doran, Harold wrote:
> > I have a data set where I want the correlations between 2 variables 
> > conditional on a students grade level.
> > 
> > This code works just fine.
> > 
> > by(tmp[,c('mtsc07', 'DCBASmathscoreSPRING')], tmp$Grade, cor, 
> > use='complete', method='pearson')
> > 
> > However, this generates an error
> > 
> > by(tmp[,c('mtsc07', 'DCBASmathscoreSPRING')], tmp$Grade, cor, 
> > use='complete', method='spearman') Error in FUN(data[x, ], 
> ...) : 'x' 
> > is empty
> > 
> > I can subset the data by grade and compute spearman rho as
> > 
> > tmp5 <- subset(tmp, Grade == 5)
> > cor(tmp5[,c('mtsc07', 'DCBASmathcountSPRING')], use='complete',
> > method='spearman')
> > 
> > But doing this iteratively is inefficient.
> > 
> > I don't see anything in the help man for by() or cor() that 
> tells me 
> > what the problem is. I might be missing it though. Any thoughts?
> 
>   It works as expected using the iris data:
> 
> by(iris[,c('Sepal.Length', 'Sepal.Width')], iris$Species, cor,
>    use='complete', method='spearman')
> 
> iris$Species: setosa
>              Sepal.Length Sepal.Width
> Sepal.Length    1.0000000   0.7553375
> Sepal.Width     0.7553375   1.0000000
> --------------------------------------------------------------
> -------------------------------------------------------
> 
> iris$Species: versicolor
>              Sepal.Length Sepal.Width
> Sepal.Length     1.000000    0.517606
> Sepal.Width      0.517606    1.000000
> --------------------------------------------------------------
> -------------------------------------------------------
> 
> iris$Species: virginica
>              Sepal.Length Sepal.Width
> Sepal.Length    1.0000000   0.4265165
> Sepal.Width     0.4265165   1.0000000
> 
> > sessionInfo()
> R version 2.5.1 Patched (2007-09-16 r42884)
> i386-pc-mingw32
> 
> locale:
> LC_COLLATE=English_United States.1252;LC_CTYPE=English_United
> States.1252;LC_MONETARY=English_United
> States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252
> 
> attached base packages:
> [1] "stats"     "graphics"  "grDevices" "utils"     "datasets"
> "methods"   "base"
> 
> other attached packages:
>  lattice
> "0.16-5"
> 
> > Thanks,
> > Harold
> > 
> > 
> >> sessionInfo()
> > R version 2.5.0 (2007-04-23)
> > i386-pc-mingw32
> > 
> > locale:
> > LC_COLLATE=English_United States.1252;LC_CTYPE=English_United
> > States.1252;LC_MONETARY=English_United
> > States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252
> > 
> > attached base packages:
> > [1] "stats"     "graphics"  "grDevices" "utils"     "datasets"
> > "methods"   "base"     
> > 
> > other attached packages:
> >  lattice
> > "0.15-4" 
> > 
> > 
> > 	[[alternative HTML version deleted]]
> > 
> > ______________________________________________
> > 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. 
> 
> --
> Chuck Cleland, Ph.D.
> NDRI, Inc.
> 71 West 23rd Street, 8th floor
> New York, NY 10010
> tel: (212) 845-4495 (Tu, Th)
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>