# [R] beginner Q: hashtable or dictionary?

Gabor Grothendieck ggrothendieck at gmail.com
Mon Jan 30 04:54:05 CET 2006

```One could also use a matrix if appropriate:

> m <- matrix(1:4, 2, dimnames = list(c("a", "b"), c("a", "b")))
> m["a", "b"]
[1] 3

Also in the 1d case one could do this:

v <- c(a = 1, b = 2)
v[["a"]]

On 1/29/06, Gabor Grothendieck <ggrothendieck at gmail.com> wrote:
> Make a list of lists:
>
> L <- list(a = list(a = 1, b = 2), b = list(a = 3, b = 4))
> L[["a"]][["b"]]
> L\$a\$b
>
> On 1/29/06, Christos Hatzis <christos at nuverabio.com> wrote:
> > I was wondering if there is an easy way to extend this to implement a 2-D
> > hash, i.e. 2-way indexing?
> >
> > > x[["a"]][["b"]] <- "something"
> >
> > Thanks.
> >
> > Christos Hatzis
> >
> > -----Original Message-----
> > From: r-help-bounces at stat.math.ethz.ch
> > [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of jim holtman
> > Sent: Sunday, January 29, 2006 8:39 PM
> > To: context grey
> > Cc: r-help at stat.math.ethz.ch
> > Subject: Re: [R] beginner Q: hashtable or dictionary?
> >
> > use a 'list':
> >
> >
> > > x <- list()
> > > x[['test']] <- 64
> > > x[['next one']] <- c(1,2,3,4)
> > > x
> > \$test
> > [1] 64
> >
> > \$"next one"
> > [1] 1 2 3 4
> >
> > > x[['test']]
> > [1] 64
> > >
> >
> >
> >
> > On 1/29/06, context grey <mobygeek at yahoo.com> wrote:
> > >
> > > Hi,
> > >
> > > Is there something like a hashtable or (python) dictionary in R/Splus?
> > >
> > > (If not, is there a reason why it's not needed / typical way to
> > > accomplish the same thing?)
> > >
> > > Thank you
> > >
> > > ______________________________________________
> > > R-help at stat.math.ethz.ch mailing list
> > > https://stat.ethz.ch/mailman/listinfo/r-help
> > > http://www.R-project.org/posting-guide.html
> > >
> >
> >
> >
> > --
> > Jim Holtman
> > Cincinnati, OH
> > +1 513 247 0281
> >
> > What the problem you are trying to solve?
> >
> >        [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help at stat.math.ethz.ch mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > http://www.R-project.org/posting-guide.html
> >
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