Or, using your mapply solution, compute
rs <- rowSums(mat1)
and then use it for all subtractions. With a larger dataset this would
be probably faster.
Rui Barradas
Em 05-10-2012 22:41, arun escreveu:
Hi,
Sorry, I think I misunderstand your question (after reading Rui's solution).
You can also try any of these to get the result if this is what you meant:
set.seed(1)
mat1<-matrix(sample(1:500,380,replace=TRUE),ncol=38)
res1<-t(do.call(rbind,lapply(1:ncol(mat1), function(i)
mat1[,i]-apply(mat1,1,sum))))
#or
res1<-sapply(1:ncol(mat1), function(i) mat1[,i]-apply(mat1,1,sum))
#or
res1<-mapply(FUN=function(i) mat1[,i]-rowSums(mat1), 1:ncol(mat1))
A.K
----- Original Message -----
From: eliza botto <eliza_bo...@hotmail.com>
To: "r-help@r-project.org" <r-help@r-project.org>
Cc:
Sent: Friday, October 5, 2012 4:05 PM
Subject: [R] loop for column substraction of a matrix
Dear useRs,
I have a matrix with 38 columns and 365 rows. what i want to do is the
following.....
1. subtracting from each column, first itself and then all the remaining
columns. More precisely, from column number 1, i will first subtract
itself(column 1) and then the remaining 37 columns. Afterwards i will take
column number 2 and do the same. In this way i want to proceed till 38th column.
2. i want to print the resulting matrix on A4 paper.
Bundle of thanks in advance.
best regards
eliza
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