[R] Trouble Combining With Paste

[Joshua Wiley]

Hi John,

The issue is that:

"infert$age" != infert$age

One is a text string, the other references the information stored in
the age variable of the infert object.  If you need to pass the names
as a string, use "[" instead:

## for a data frame
infert[, "age"]
## for a list
infert[["age"]]

It looks like from your code maybe: infert[, attr(toolong[1],"names")]

HTH,

Josh


On Wed, May 25, 2011 at 9:02 AM, Sparks, John James <jspark4 at uic.edu> wrote:
> Dear R Helpers,
>
> I am having trouble combining some pieces of programming that work fine
> individually, but fall down when I try to get them to work together.
>
> The end goal is to take a data frame, and if any of the variables has more
> than 10 values, then use cut2 to reduce the number of (effective) values
> to 10.  I want to do this in automated fashion, which is where the
> combining comes in.
>
> For example all of these pieces work as I would expect:
>
>
> tables<-lapply(infert,table)
> lengths<-lapply(tables,length)
> toolong<-which(lengths>10)
>
> require(Hmisc)
>
> foo<-as.numeric(cut2(infert$age,g=10,levels.mean=TRUE))
> str(foo)
> #num [1:248] 2 10 9 7 7 8 1 6 1 3 ...
>
> bar<-paste("inftert$",attr(toolong[1],"names"),sep="")
> bar
> #[1] "inftert$age"
>
> But the following gives an error:
>
> foobar<-as.numeric(cut2(paste("inftert$",attr(toolong[1],"names"),sep=""),g=10,levels.mean=TRUE))
> Error in min(diff(x.unique))/2 : non-numeric argument to binary operator
> In addition: Warning message:
> In min(diff(x.unique)) : no non-missing arguments, returning NA
>
>
> Your guidance would be much appreciated.
>
> --John J. Sparks, Ph.D.
>
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>



-- 
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/