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

From: jim holtman <jholtman_at_gmail.com>
Date: Thu, 26 Jun 2008 12:42:11 -0400

Is this what you want

> dt <- data.frame(a = c(1, 2, 3), b = c(3, 2, 2), c = c(1, 3, 5))
> for (i in 1:2){

+ dt[[paste('test',i,sep="")]] <- rep(i,3) + }
> dt

  a b c test1 test2

1 1 3 1     1     2
2 2 2 3     1     2
3 3 2 5     1     2

>

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
>
> ______________________________________________
> R-help_at_r-project.org mailing list
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?

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Received on Thu 26 Jun 2008 - 16:46:15 GMT

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