R help - Jun 2007 - Selecting all values smaller than X in a dataframe

Dear R users,

I have a correlation matrix for a dataframe called "synth", for which
I
now want to select only those cells that have correlations larger than 
+/-0.6:

synth=data.frame(x=rnorm(10,1),y=rnorm(10,2),z=rnorm(10,0.5))

w=cor(synth,use="pairwise.complete.obs")
w=as.data.frame(w)
w[,sapply(w,abs(w),">",0.6)]

The problem is that using sapply with ">" or "<"
doesn?t seem to work.

How could I solve this problem?

Thank you very much in advance for your help!

Best wishes
Christoph

(I am using R 2.5.0 on Windows XP).



--
Christoph Scherber
DNPW, Agroecology
University of Goettingen
Waldweg 26
D-37073 Goettingen

+49-(0)551-39-8807

Christoph Scherber-2 wrote:
> 
> Dear R users,
> 
> I have a correlation matrix for a dataframe called "synth", for
which I
> now want to select only those cells that have correlations larger than 
> +/-0.6:
> 
> synth=data.frame(x=rnorm(10,1),y=rnorm(10,2),z=rnorm(10,0.5))
> 
> w=cor(synth,use="pairwise.complete.obs")
> w=as.data.frame(w)
> w[,sapply(w,abs(w),">",0.6)]
> 
> The problem is that using sapply with ">" or "<"
doesn?t seem to work.
> 
> How could I solve this problem?
> 
> 
If you want to extract correlations with absolute value >0.6, then simply
use w[abs(w)>0.6]

Please, reread the help("sapply"). You give some extra arguments to
this
function.
The first goes the vector, the second goes the function, and then -
additional arguments to the function.
Probably, you wanted w[sapply(abs(w),">",0.6)]
This gives the same result.

-- 
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Hi

r-help-bounces at stat.math.ethz.ch napsal dne 11.06.2007 14:09:45:
> Dear R users,
> 
> I have a correlation matrix for a dataframe called "synth", for
which I
> now want to select only those cells that have correlations larger than 
> +/-0.6:
> 
> synth=data.frame(x=rnorm(10,1),y=rnorm(10,2),z=rnorm(10,0.5))
> 
> w=cor(synth,use="pairwise.complete.obs")
> w=as.data.frame(w)
Why? Better is tu use

abs(w)>.6

and/or

which(abs(w)>.6, arr.ind=T)

or, if you want actual values just

w[abs(w)>.6]

Regards

Petr
> w[,sapply(w,abs(w),">",0.6)]
> 
> The problem is that using sapply with ">" or "<"
doesn?t seem to work.
> 
> How could I solve this problem?
> 
> Thank you very much in advance for your help!
> 
> Best wishes
> Christoph
> 
> (I am using R 2.5.0 on Windows XP).
> 
> 
> 
> --
> Christoph Scherber
> DNPW, Agroecology
> University of Goettingen
> Waldweg 26
> D-37073 Goettingen
> 
> +49-(0)551-39-8807
> 
> ______________________________________________
> R-help at stat.math.ethz.ch 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.

Christoph Scherber <Christoph.Scherber <at> agr.uni-goettingen.de>
writes:
> 
> Dear R users,
> 
> I have a correlation matrix for a dataframe called "synth", for
which I
> now want to select only those cells that have correlations larger than 
> +/-0.6:
> 
> synth=data.frame(x=rnorm(10,1),y=rnorm(10,2),z=rnorm(10,0.5))
> 
> w=cor(synth,use="pairwise.complete.obs")
> w=as.data.frame(w)
> w[,sapply(w,abs(w),">",0.6)]
 

Dear Christoph,

just change the last command to

w[abs(w)>0.6]


Best wishes
Ingo