R help - Sep 2012 - pairwise comparisions

Hi ,
 I am new to R . I am facing difficulty how to make pairwise comparisions.
For example. I have a file which looks like below
   a b c d
x  3 6 7 6
y  7 8 6 5
z  5 4 7 8
Here I need to look for the each pairwise comparisions (ab,ac,ad,bc,bd,cd
for each row)
For instance ,looking at first row, for x i need to look for ab values and
take the min(3,6) >5 ,if its satistfies the count should be noted, (now
count is 0), bc values ,min(6,7) >5 ,count for x =1 etc. Likewise all the
comparisons are made and count is noted for x,y,z. 
Is there any function to make pairwise comparisions in R or any easy way to
do this?
Any help is greatly appreciated. 



--
View this message in context:
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1. Be forewarned: There may be special approaches built into specific
packages that are better than "generalist" approaches like the one I
suggest here.

2. The general approach to this sort of thing is with ?outer, if I
understand you correctly.

3. Have you read an Introduction to R (ships with every copy of R)? If
not, stop and read it before posting further to this list, as it may
well contain answers to the questions you wish to pose here.

Cheers,
Bert

On Mon, Sep 10, 2012 at 7:00 AM, priya <jaggari_ash at yahoo.co.in>
wrote:
> Hi ,
>  I am new to R . I am facing difficulty how to make pairwise comparisions.
> For example. I have a file which looks like below
>    a b c d
> x  3 6 7 6
> y  7 8 6 5
> z  5 4 7 8
> Here I need to look for the each pairwise comparisions (ab,ac,ad,bc,bd,cd
> for each row)
> For instance ,looking at first row, for x i need to look for ab values and
> take the min(3,6) >5 ,if its satistfies the count should be noted, (now
> count is 0), bc values ,min(6,7) >5 ,count for x =1 etc. Likewise all
the
> comparisons are made and count is noted for x,y,z.
> Is there any function to make pairwise comparisions in R or any easy way to
> do this?
> Any help is greatly appreciated.
>
>
>
> --
> View this message in context:
http://r.789695.n4.nabble.com/pairwise-comparisions-tp4642656.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.


-- 

Bert Gunter
Genentech Nonclinical Biostatistics

Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm

On Sep 10, 2012, at 7:00 AM, priya wrote:
> Hi ,
> I am new to R .
How new? Is this still in a file? ... or has it been imported to an R object. If
it really still is in a file,  then Bert's suggestion of first reading
"Intro to R" rather than posting to R help is on point. If it is an R
object, you _should_ have used dput(head(obj)) to provide an appropriate test
case for solutions.
> I am facing difficulty how to make pairwise comparisions.
> For example. I have a file which looks like below
>   a b c d
> x  3 6 7 6
> y  7 8 6 5
> z  5 4 7 8
> Here I need to look for the each pairwise comparisions (ab,ac,ad,bc,bd,cd
> for each row)
Let's assume it's in a matrix of data.frame named X. To get pairwise
combinations try:

CX <- combn( colnames(X), 2)

That's going to be a 2 row character matrix. Perhaps this will work but
since you provide not example it will remain untested.

apply(CX, 2, function(comb), pmin(X[, comb[1]], X[, comb[2]] ) )
> For instance ,looking at first row, for x i need to look for ab values and
> take the min(3,6) >5 ,if its satistfies the count should be noted, (now
> count is 0), bc values ,min(6,7) >5 ,count for x =1 etc. Likewise all
the
> comparisons are made and count is noted for x,y,z. 
> Is there any function to make pairwise comparisions in R or any easy way to
> do this?
> Any help is greatly appreciated. 
-- 

David Winsemius, MD
Alameda, CA, USA