Re: [R] create new column with colnames resulting from paste()

From: Jorge Ivan Velez <jorgeivanvelez_at_gmail.com>
Date: Thu, 26 Jun 2008 12:34:42 -0400

Dear Dong-hyun,

What about

dt <- data.frame(a = c(1, 2, 3), b = c(3, 2, 2), c = c(1, 3, 5))
test=matrix(rep(c(1,2),each=3),ncol=2)
colnames(test)=paste('test',1:2,sep="")

cbind(dt,test)

?

HTH, Jorge

On Thu, Jun 26, 2008 at 12:23 PM, Dong-hyun Oh <r.arecibo_at_gmail.com> wrote:

> Dear UseRs,
>
> I would like to know the way to create a new column by naming it
> simultaneously.
> For example, in for() loop I want to create columns named as paste("test",
> i, sep = ""), as shown below.
>
> ----------------------------
> dt <- data.frame(a = c(1, 2, 3), b = c(3, 2, 2), c = c(1, 3, 5))
>
> for(i in 1:2){
> dt$as.name(paste("test", i, sep = "")) <- rep(i, 3)
> }
> --------------------------
>
> Error message of above command is as follows:
> --------------------------
> Error in dt$as.name(paste("test", i, sep = "")) <- rep(i, 3) :
> target of assignment expands to non-language object
> --------------------------
>
>
> The structure of data.frame I want is as follows:
> > dt
> a b c test1 test2
> 1 3 2 1 2
> 2 2 3 1 2
> 3 2 5 1 2
>
> Any help?
>
> Thank you in advance.
>
> Best,
>
>
>
> =========================================================
> Dong-hyun Oh
> Center of Excellence for Science and Innovation Studies
> Royal Institute or Technology, Sweden
> e-mail: oh.dongh_at_gmail.com
> cel: +46 73 563 45 22
>
> ______________________________________________
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>

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