no need for a for loop - we can vectorize this:
> dt <- data.frame(a = c(1, 2, 3), b = c(3, 2, 2), c = c(1, 3, 5))
> dt
a b c
1 1 3 1
2 2 2 3
3 3 2 5
> dt[,paste("test", 1:2, sep="")] = rep(1:2, each=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 06/26/2008 12:42 PM jim holtman said the following:
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 <[EMAIL PROTECTED]> 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: [EMAIL PROTECTED]
cel: +46 73 563 45 22
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