[R] Simple R Question...

[David Winsemius]

On May 21, 2011, at 7:37 AM, Lars Bishop wrote:

> Let's say I have the data frame 'dd' below. I'd like to select one
> column from this data frame (say 'a') and keep its name in the
> resulting data frame. That can be done as in #2. However, what if I
> want to make my selection based on a vector of names (and again keep
> those names in the resulting data frame). My attempt is #4 but doesn't
> work.
>
> dd <- data.frame(a = gl(3,4), b = gl(4,1,12), c=rnorm(12)) #1
> data.frame("a" = dd[,"a"]) #2
>
> mynames <- "a" #3
> data.frame(eval(mynames) = dd[, mynames]) #4

dd[mynames]

(Will succeed with a vector of names as well.)


>
> thanks,
> Lars.
>
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David Winsemius, MD
West Hartford, CT