[R] matrix of all difference between rows values

[arun]

HI,
No problem.

You can also use ?aaply() from library(plyr)
dat1<-read.table(text="
 a         10
         b         9
         c         8
         d         7
         e         6
",sep="",header=FALSE,stringsAsFactors=FALSE)
library(plyr) 

res1<-aaply(dat1[1,2],1,"-",toeplitz(dat1[,2]))
 res1[upper.tri(res1)]<- -1*res1[upper.tri(res1)] 
rownames(res1)<-colnames(res1)<-dat1[,1] 
 res1
   
#    a  b  c  d  e
 # a 0 -1 -2 -3 -4
 # b 1  0 -1 -2 -3
  #c 2  1  0 -1 -2
  #d 3  2  1  0 -1
  #e 4  3  2  1  0

#or

res2<-matrix(mapply("-",dat1[1,2],toeplitz(dat1[,2])),ncol=5)
#or
#res2<- matrix(sapply(toeplitz(dat1[,2]),function(x) dat1[1,2]-x),ncol=5)
res2[upper.tri(res2)]<- -1*res2[upper.tri(res2)]
dimnames(res2)<-dimnames(res1)
identical(res2,res1)
#[1] TRUE
A.K.



----- Original Message -----
From: cleberchaves <cleberchaves at gmail.com>
To: r-help at r-project.org
Cc: 
Sent: Saturday, November 10, 2012 2:25 PM
Subject: Re: [R] matrix of all difference between rows values

Thank you very much, arun kirshna!

That's it! I only modified the "res1<-apply(toeplitz(dat1[,2]),1,function(x)
10-x)" for "res1<-apply(toeplitz(dat1[,2]),1,function(x) dat1[1,2]-x)" and
worked very well!

Thanks again!



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