[R] help matching rows of a data frame

[Bert Gunter]

Yes. My understanding is that you want the identifier to have the same
number of rows as the data frame. A slight variant of David's solution
would then be:

do.call(paste0,x)


-- Bert



On Mon, Sep 18, 2017 at 8:29 AM, David Winsemius <dwinsemius at comcast.net>
wrote:

>
> > On Sep 18, 2017, at 5:13 AM, Therneau, Terry M., Ph.D. <
> therneau at mayo.edu> wrote:
> >
> > This question likely has a 1 line answer, I'm just not seeing it.  (2,
> 3, or 10 lines is fine too.)
> >
> > For a vector I can do group  <- match(x, unqiue(x)) to get a vector that
> labels each element of x.
> > What is an equivalent if x is a data frame?
> >
>
> In the past I've use apply with past to generate "group" identifiers:
>
>
> x<-data.frame("X0"=c("A","B","C","C","D","A"), "X1"=c(1,2,1,1,3,1))
>
> apply(x, 1, paste, collapse=".")
> [1] "A.1" "B.2" "C.1" "C.1" "D.3" "A.1"
>
>
> > The result does not have to be fast: the data set will have < 100
> elements.  Since this is inside the survival package, and that package is
> on  the 'recommended' list, I can't depend on any package outside the
> recommended list.
>
> David Winsemius
> Alameda, CA, USA
>
> 'Any technology distinguishable from magic is insufficiently advanced.'
>  -Gehm's Corollary to Clarke's Third Law
>
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