Re: [igraph] basic question on selecting a vertex

[Gábor Csárdi]

On Tue, Mar 20, 2012 at 2:20 PM, Charles Novaes de Santana
<address@hidden> wrote:
> Hi Simone,
>
> Considering you have the names of your vertices in a variable named
> "vertices", in a very straightforward way you could do:
>
> v1<-which(vertices=="this");
> v2<-which(vertices=="that");
> g<-add.edges(g,c(v1,v2));

This is good, except that you need to subtract one, because vertices
are numbered from zero.

G.

> So, the R function you are looking for is called "which".
>
> Surely there are other (more elegant) ways to do it, but that is the
> one I remember now.
>
> All the best,
>
> Charles
>
> On Tue, Mar 20, 2012 at 6:59 PM, Simone Gabbriellini
> <address@hidden> wrote:
>> Dear List,
>>
>> sorry for this very basic question, but I am trying to select a vertex
>> based on the value of an attribute. I forgot the R syntax, and I got
>> lost trying to pick it up again...
>>
>> I would like to create an edge between two nodes for which I only know
>> the value of the attribute, like:
>>
>> add.edges(g, c( the-ID-of-vertex-with-name=="this",
>> the-ID-of-vertex-with-name=="that"))
>>
>> can you please advice?
>>
>> Best,
>> Simone
>>
>> --
>> Dr. Simone Gabbriellini
>>
>> DigitalBrains srl
>> Amministratore
>>
>> mobile: +39 3403975626
>> mail: address@hidden
>>
>> _______________________________________________
>> igraph-help mailing list
>> address@hidden
>> https://lists.nongnu.org/mailman/listinfo/igraph-help
>
>
>
> --
> Um axé! :)
>
> --
> Charles Novaes de Santana
> http://www.imedea.uib-csic.es/~charles
> PhD student - Global Change
> Laboratorio Internacional de Cambio Global
> Department of Global Change Research
> Instituto Mediterráneo de Estudios Avanzados(CSIC/UIB)
> Calle Miquel Marques 21, 07190
> Esporles - Islas Baleares - España
>
> Office phone - +34 971 610 896
> Cell phone - +34 660 207 940
>
> _______________________________________________
> igraph-help mailing list
> address@hidden
> https://lists.nongnu.org/mailman/listinfo/igraph-help



-- 
Gabor Csardi <address@hidden>     MTA KFKI RMKI