[R] unique combinations

[Uwe Ligges]

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...
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>> 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.