[R] Creating and assigning variable names in loop

[andrija djurovic]

Hi. You assign two times different values to variable label. Try this
and i hope you will notice a mistake:

i=1
label <- paste("score", i, sep="_")
label
assign("label", x1+(x2*i) )
label

Instead of this you can do something like:
rm(list=ls())
n = 10
set.seed(1)
x1 = rnorm(n,0)
x2 = rnorm(n,0)
samp_data <- data.frame(x1,x2)

for( i in 1:3) {
   samp_data <- cbind(samp_data, x1+(x2*i))
   colnames(samp_data)[i+2] <- paste("score", i, sep="_")
}
head(samp_data)

Andrija


On Wed, Dec 21, 2011 at 11:01 AM, aajit75 <aajit75 at yahoo.co.in> wrote:
> Hello List
>
> I am trying to create and assign variable names in loop, but not able to get
> expected variable names.
>
> Here is the sample code
>
> n = 10
> set.seed(1)
> x1 = rnorm(n,0)
> x2 = rnorm(n,0)
> samp_data <- data.frame(x1,x2)
>
> for( i in 1:3) {
>    label <- paste("score", i, sep="_")
>    assign(label, value =x1+(x2*i) )
>    samp_data <- cbind(samp_data, get(label))
> }
>
>> head(samp_data)
>          x1                    x2          get(label)     get(label)
> get(label)
> 1 -0.6264538  1.51178117  0.8853274  2.3971085  3.9088897
> 2  0.1836433  0.38984324  0.5734866  0.9633298  1.3531730
> 3 -0.8356286 -0.62124058 -1.4568692 -2.0781098 -2.6993504
> 4  1.5952808 -2.21469989 -0.6194191 -2.8341190 -5.0488189
> 5  0.3295078  1.12493092  1.4544387  2.5793696  3.7043005
> 6 -0.8204684 -0.04493361 -0.8654020 -0.9103356 -0.9552692
>
> I am expecting new variables to be created in the samp_data are
> score_1   score_2   score_3, instead get(label)   get(label)   get(label)
> Where am I going wrong?
>
> Thanks in advance
> ~Ajit
>
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