R help - Jan 2014 - passing variable names to dplyr

All,

I would like to figure out how to pass variable names to the dplyr function
mutate.  For example, this works because hp is one of the variable names on
mtcars:

mutate(mtcars, scale(hp))

Let's says I want to pass in the target variable instead of hard-coding the
name, as follows:

target <- "hp"
mutate(mtcars, scale(target))

That dones't work.  I read somewhere about using lapply, but that suggestion
didn't work for me either:

target <- lapply("hp", as.symbol)
mutate(mtcars, scale(target))

Does anyone know how to do this?

Thanks,

Roger

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On Jan 27, 2014, at 7:45 AM, Bos, Roger wrote:
> All,
> 
> I would like to figure out how to pass variable names to the dplyr function
mutate.  For example, this works because hp is one of the variable names on
mtcars:
> 
> mutate(mtcars, scale(hp))
> 
> Let's says I want to pass in the target variable instead of hard-coding
the name, as follows:
> 
> target <- "hp"
> mutate(mtcars, scale(target))
> 
> That dones't work.  I read somewhere about using lapply, but that
suggestion didn't work for me either:
> 
> target <- lapply("hp", as.symbol)
> mutate(mtcars, scale(target))
> 
> Does anyone know how to do this?
You cross-posted this to the manipulatr newsgroup (where it was addressed).
Crossposting is a practice which is not appreciated in R lists.

--

David Winsemius
Alameda, CA, USA