R help - Nov 2012 - Efficiently creating/defining new variables transformations

I would like to add an extension to the current name of a variable to create
a new variable that is its sqrt transform. Each piece of the equation below
works independently, but the left side definition fails on run. I also tried
creating the variable name first, but ended up with an object that
toString() did not fix. Better ideas?

Example 1
(paste0(emotions[[i]],"_sqrt"))<-sqrt(data[[emotions[i]]])

Example 2
newvar<-toString(paste0(emotions[[i]],"_sqrt"))
data$newvar<-sqrt(data[[emotions[i]]])

Example 3
newvar<-toString(paste0(emotions[[i]],"_sqrt"))
data$newvar[1]<-sqrt(data[[emotions[i]]])



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On Nov 21, 2012, at 4:35 PM, nprause wrote:
> I would like to add an extension to the current name of a variable to
create
> a new variable that is its sqrt transform. Each piece of the equation below
> works independently, but the left side definition fails on run. I also
tried
> creating the variable name first, but ended up with an object that
> toString() did not fix. Better ideas?
> 
> Example 1
> (paste0(emotions[[i]],"_sqrt"))<-sqrt(data[[emotions[i]]])
Easiest way would be to use "[[<-" (since there is no
'paste0<-' function:

data[[ paste0(emotions[[i]],"_sqrt") ] <- sqrt(data[[ emotions[i]
]])

Now I'm pretty sure that would not work as it stands if the length of
"i" were greater than 1, but if "i" were a single number or
character value being delivered inside a loop or equivalently inside sapply(),
it should work.

You can also look at:

?assign
> 
> Example 2
> newvar<-toString(paste0(emotions[[i]],"_sqrt"))
> data$newvar<-sqrt(data[[emotions[i]]])
> 
> Example 3
> newvar<-toString(paste0(emotions[[i]],"_sqrt"))
> data$newvar[1]<-sqrt(data[[emotions[i]]])
> 
> 
> 
> --
> View this message in context:
http://r.789695.n4.nabble.com/Efficiently-creating-defining-new-variables-transformations-tp4650401.html
> Sent from the R help mailing list archive at Nabble.com.
> 
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David Winsemius, MD
Alameda, CA, USA