[R] unique combinations

[Jeff Newmiller]

On Wed, 21 Dec 2011, Keith Jewell wrote:

> Thanks Uwe,
>
> I was happy that my 2 lines gave what the OP asked for, albeit in a
> different order.
>
> My puzzlement arose from Jeff Newmillers comment:
>> You could read the help for expand.grid very carefully for the answer to
>> this question.
> ... which I reas as saying that ?expand.grid would lead to a solution.
> I used "[", which I couldn't see suggested on ?expand.grid.
> I thought I'd missed a neater solution in the help pages, and hoped someone
> could point it out.

Sorry, I jumped the gun.  Peter's answer addressed the identical elements 
issue much more thoroughly than my oblique reference to combn. I just 
didn't recognize the same-element issue.

> Best regards,
>
> Keith Jewell
> ------------------------------
> "Uwe Ligges" <ligges at statistik.tu-dortmund.de> wrote in message
> news:4EF1EC69.2080707 at statistik.tu-dortmund.de...
>>
>>
>> On 21.12.2011 14:39, Keith Jewell wrote:
>>> OK, someone point it out to me; my wife tells me I can't see what's in
>>> front
>>> of me :-}
>>>
>>> I read ?expand.grid carefully, went to ?combn and ?choose but still
>>> couldn't
>>> see an easy way to get what the OP asked for. The neatest I can get
>>> (which
>>> isn't very neat!) is:
>>>
>>>> myVec<- c(1,2,3)
>>>> eg<- expand.grid(myVec, myVec)
>>>> eg[eg[,1]<= eg[,2],]
>>>    Var1 Var2
>>> 1    1    1
>>> 4    1    2
>>> 5    2    2
>>> 7    1    3
>>> 8    2    3
>>> 9    3    3
>>>
>>> What am I missing?
>>
>> You are just using a different order - sort accoriding to Var1...
>>
>> Best,
>> Uwe Ligges
>>
>>>
>>> Best regards,
>>>
>>> KJ
>>> "Jeff Newmiller"<jdnewmil at dcn.davis.ca.us>  wrote in message
>>> news:80cc9ff9-d867-4dfc-b6e3-9c1df782209a at email.android.com...
>>>> You could read the help for expand.grid very carefully for the answer to
>>>> this question.
>>>> ---------------------------------------------------------------------------
>>>> Jeff Newmiller                        The     .....       .....  Go
>>>> Live...
>>>> DCN:<jdnewmil at dcn.davis.ca.us>         Basics: ##.#.       ##.#.  Live
>>>> Go...
>>>>                                       Live:   OO#.. Dead: OO#..  Playing
>>>> Research Engineer (Solar/Batteries            O.O#.       #.O#.  with
>>>> /Software/Embedded Controllers)               .OO#.       .OO#.
>>>> rocks...1k
>>>> ---------------------------------------------------------------------------
>>>> Sent from my phone. Please excuse my brevity.
>>>>
>>>> Antje Niederlein<niederlein-rstat at yahoo.de>  wrote:
>>>>
>>>>> Hi there,
>>>>>
>>>>> I have a vector and would like to create a data frame, which contains
>>>>> all unique combination of two elements, regardless of order.
>>>>>
>>>>> myVec<- c(1,2,3)
>>>>>
>>>>> what expand.grid does:
>>>>>
>>>>> 1,1
>>>>> 1,2
>>>>> 1,3
>>>>> 2,1
>>>>> 2,2
>>>>> 2,3
>>>>> 3,1
>>>>> 3,2
>>>>> 3,3
>>>>>
>>>>> what I would like to have
>>>>>
>>>>> 1,1
>>>>> 1,2
>>>>> 1,3
>>>>> 2,2
>>>>> 2,3
>>>>> 3,3
>>>>>
>>>>> Can anybody help?
>>>>>
>>>>> ______________________________________________
>>>>> R-help at 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.
>>>>
>>>
>>> ______________________________________________
>>> R-help at 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.
>>
>
> ______________________________________________
> R-help at 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.
>

---------------------------------------------------------------------------
Jeff Newmiller                        The     .....       .....  Go Live...
DCN:<jdnewmil at dcn.davis.ca.us>        Basics: ##.#.       ##.#.  Live Go...
                                       Live:   OO#.. Dead: OO#..  Playing
Research Engineer (Solar/Batteries            O.O#.       #.O#.  with
/Software/Embedded Controllers)               .OO#.       .OO#.  rocks...1k