[R] Subset with selection variable from function argument. Is there another way?

[Uwe Ligges]

Fredrik Karlsson wrote:

> Dear list,
> 
> I'm making my current code more generic and would like some advise.
> The basic problem is subset and the name of the column to be compared
> for selection.
> 
> What I've come up with is 
> 
> 
>>data(mammals)
>>set <- bottompremolars"

The line above is
  a) syntactically incorrect and
  b) the string does not describe a variable in the mammals data
hence this is not reproducible at all.

>>subset(mammals, eval(parse(file="",text=set)) > 2)
>

Let's assume
   set <- "body"

Either use get() as in
   subset(mammals, get(set) > 2)
or simple indexing such as:
   subset(mammals, mammals[[set]] > 2)


Uwe Ligges



> 
> This seems a bit odd.  Is there a nicer way?
> 
> /Fredrik
> 
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