Re: [R] how to extract the row names of a matrix using for loop or otherlooping

From: ronggui <042045003_at_fudan.edu.cn>
Date: Sun 11 Dec 2005 - 15:40:38 EST


lapply and rownames will do what you want

> class(t)

[1] "list"
> lapply(t,rownames)
[[1]]
[1] "ca" "cd"

[[2]]
[1] "cb"

[[3]]
[1] "cc"

>Hi all,
> I have a matrix and its cluster...and i like to extract the row names of each cluster....but using the for loop or some other looping
>
> a<-matrix(c(seq(3,45,3),seq(10,6,-1)),4,5,byrow=F)
> col<-c("ra","rb","rc","rd","re")
> rows<-c("ca","cb","cc","cd")
> dimnames(a)<-list(rows,col)
>a ## matrix
> #-----------------------------------------------------------------------------------
> # ra rb rc rd re
># ca 3 15 27 39 9
># cb 6 18 30 42 8
># cc 9 21 33 45 7
># cd 12 24 36 10 6
> ------------------------------------------------------------------------------------
>
>t<-list() ## clusters of the matrix
> s<-list()
> r<-c(1:3)
> for(i in 1:3)
>{ p<-seq(r[i],4,3)
> s[[i]]<-print(p)
>t[[i]]<-a[s[[i]],,drop=FALSE]
> }
>print(t)
> ----------------------------------------------------------------------
> ##[[1]]
> ra rb rc rd re
>ca 3 15 27 39 9
>cd 12 24 36 10 6
> [[2]]
> ra rb rc rd re
>cb 6 18 30 42 8
> [[3]]
> ra rb rc rd re
>cc 9 21 33 45 7
>----------------------------------------------------------------------------------------------------
>
>
> ##now if i want to extract the row names i can do it manually giving the values like
>
> rowc <- list(c(rownames(t[[1]])), c(rownames(t[[2]])), rownames(t[[3]]))
>
>
> but i like to do using for loop or other loops...could you give me some suggestion..i磛e tried like this..but it is not working....
>
> rowc<-list(for(i in 1:3){p<-c();k<-rownames(t[[i]]);p[[i]]<-print(k)})
>
> ## here I磎 getting only the final rowname t[[3]]..other two values are missing..how could i do this to store all the values...........
>
> thank you...
>
> with regards,
> eric.
>
>
>---------------------------------
>
>
> [[alternative HTML version deleted]]
>
>
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2005-12-11



Deparment of Sociology
Fudan University

My new mail addres is ronggui.huang@gmail.com Blog:http://sociology.yculblog.com



R-help@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 Received on Sun Dec 11 15:47:16 2005

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