R help - May 2005 - List and Column Names in a Function?

In this simple function, how can I pass strings for index and column names
to the function?  I've posted this type of question before and received no
response.

Maybe this example will be easier to understand and troubleshoot.

ds <- function(myds, vec) {myds[[vec]]*2}

ds1 <- c(X=list(1:10), Y=list(11:20))

ds(get("ds1"),get("Y"))


khobson at odot.org
Kenneth Ray Hobson, P.E.
Oklahoma DOT - QA & IAS Manager
Oklahoma City, OK  73105-3204

khobson at fd9ns01.okladot.state.ok.us wrote:
> 
> 
> 
> In this simple function, how can I pass strings for index and column names
> to the function?  I've posted this type of question before and received
no
> response.
> 
> Maybe this example will be easier to understand and troubleshoot.
> 
> ds <- function(myds, vec) {myds[[vec]]*2}
> 
> ds1 <- c(X=list(1:10), Y=list(11:20))
> 
> ds(get("ds1"),get("Y"))
You are overusing the get function.  I think you can do what you want as

ds(ds1, "Y")

The solution that Douglas proposed does not work.  Any other ideas?
> In this simple function, how can I pass strings for index and column
names
> to the function?  I've posted this type of question before and received
no
> response.
>
> Maybe this example will be easier to understand and troubleshoot.
>
> ds <- function(myds, vec) {myds[[vec]]*2}
>
> ds1 <- c(X=list(1:10), Y=list(11:20))
>
> ds(get("ds1"),get("Y"))
You are overusing the get function.  I think you can do what you want as

ds(ds1, "Y")


khobson at odot.org
Kenneth Ray Hobson, P.E.
Oklahoma DOT - QA & IAS Manager

> From: khobson at fd9ns01.okladot.state.ok.us
> 
> The solution that Douglas proposed does not work.  Any other ideas?
Then perhaps you could (re-)read the posting guide, and give us more
information on what you mean by "does not work", and exactly what you
are
expecting?  Isn't this what you want?

> ds1 <- c(X=list(1:10), Y=list(11:20))
> ds <- function(myds, vec) myds[[vec]] * 2
> ds(ds1, "Y")
 [1] 22 24 26 28 30 32 34 36 38 40

Andy

 
> > In this simple function, how can I pass strings for index and column
> names
> > to the function?  I've posted this type of question before 
> and received
> no
> > response.
> >
> > Maybe this example will be easier to understand and troubleshoot.
> >
> > ds <- function(myds, vec) {myds[[vec]]*2}
> >
> > ds1 <- c(X=list(1:10), Y=list(11:20))
> >
> > ds(get("ds1"),get("Y"))
> 
> You are overusing the get function.  I think you can do what 
> you want as
> 
> ds(ds1, "Y")
> 
> 
> khobson at odot.org
> Kenneth Ray Hobson, P.E.
> Oklahoma DOT - QA & IAS Manager
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
> 
> 
>