Thank you both Dimitiris and Jorge Ivan!  I have just found it myself that
'combn' does what I need:

> combn(v, 2, simplify=TRUE)

is exactly what I need.

Mvh.,
Marie





On Mon, Jun 8, 2009 at 3:03 PM, Dimitris Rizopoulos <
d.rizopoulos@erasmusmc.nl> wrote:

> one way is:
>
> combn(c("a", "b", "c"), 2)
>
>
> I hope it helps.
>
> Best,
> Dimitris
>
>
> Marie Sivertsen wrote:
>
>> Dear list,
>>
>> I have a vector of elements which I want to combined each with each, but
>> none with itself. For example,
>>
>>  v <- c("a", "b", "c")
>>>
>>
>> and I need a function 'combine' such that
>>
>>  combine(v)
>>>
>> [[1]]
>> [1] "a" "b"
>>
>> [[2]]
>> [1] "a" "b"
>>
>> [[3]]
>> [1] "b" "c"
>>
>> I am not very interested in the orders of the output items for now, and
>> the
>> form can be something differs from list, like matrix or data frame. I know
>> of 'expand.grid', but it will combine each item with each item including
>> itself, so not what I wants.
>>
>> Could you help me please.  Thank you.
>>
>> Mvh.,
>> Marie
>>
>>        [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help@r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>>
> --
> Dimitris Rizopoulos
> Assistant Professor
> Department of Biostatistics
> Erasmus University Medical Center
>
> Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
> Tel: +31/(0)10/7043478
> Fax: +31/(0)10/7043014
>

	[[alternative HTML version deleted]]


