[R] selection part of "subset"

[Nordlund, Dan (DSHS/RDA)]

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Christof Kluß
> Sent: Thursday, January 05, 2012 8:04 AM
> Cc: r-help at stat.math.ethz.ch
> Subject: Re: [R] selection part of "subset"
> 
> Hi
> 
> the output should look like     r <- subset(tab, a==v)
> but now I have something like   r <- subset(tab, "a"==v)
> and                             r <- subset(tab, [["a"]]==v)
> does not work :(
> 
> greetings
> Christof
> 
> Am 05-01-2012 16:51, schrieb Christof Kluß:
> > Hi
> >
> > I want to do something like
> >
> > a <- c(10,20,15,43,76,41,25,46)
> > tab <- data.frame(a)
> >
> > name <- "a"
> >
> > for (v in unique(tab[[name]])) {
> >   r <- subset(tab, name==v)   # this does not work
> >   ...
> > }
> >
> > i.e. a "string" on the left side of the select expression (subset).
> How
> > could I solve this?


Christof,

Maybe you could look at ?get.  However, even using get(), you code probably won't work.  get(name) will return a vector, and v in your example is a scalar.   What is the task you are trying to accomplish?


Dan

Daniel J. Nordlund
Washington State Department of Social and Health Services
Planning, Performance, and Accountability
Research and Data Analysis Division
Olympia, WA 98504-5204