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## Re: [igraph] two-mode network in igraph

 From: Gábor Csárdi Subject: Re: [igraph] two-mode network in igraph Date: Fri, 24 Sep 2010 15:31:23 +0200

```On Fri, Sep 24, 2010 at 3:28 PM, Simone Gabbriellini
<address@hidden> wrote:
> Tamas,
>
> this is a much more simpler way! thanks a lot!
>
> and all I have to do is something like:
>
> V(g)\$type<-ifelse(grep("thread",V(g)\$name)==1, FALSE, TRUE)

Use 'grepl' instead of 'grep', that returns a logical vector and you
don't even need the 'ifelse'.

G.

> to set the type attribute... I know that code doesn't work, still have to
> find a way, but I got the point
>
> thanks,
> simone
>
> Il giorno 24/set/2010, alle ore 14.38, Tamas Nepusz ha scritto:
>
>>> do I have to put in the type vector one element of the first kind, one of
>>> the second kind, one of the first... etc???
>> Nope. The type vector must have N elements if you have N vertices, and the
>> i-th element must be 0 if vertex i is of the first type, or 1 if vertex i is
>> of the second type.
>>
>>> is there no way to let igraph knows about the actual names of the vertex?
>> You can use vertex attributes, but only after you have created the graph
>> with numeric vertex IDs. igraph does not allow arbitrary objects or strings
>> as vertex identifiers, only numbers.
>>
>> On the other hand, note that bipartite graphs are not special in any way in
>> igraph, so you can create a "regular" graph first using any other methods
>> (e.g., read from an NCOL file that allows vertex names, or use
>> graph.formula). The only distinguishing feature for bipartite and
>> non-bipartite graphs is the "type" vertex attribute, but you can assign that
>> later!
>>
>> For instance, suppose this is your original graph:
>>
>> author1 thread1
>> author2 thread1
>> author1 thread2
>> author3 thread2
>> author3 thread3
>>
>> Load this as an NCOL file, then go through the vertex names and create a 0-1
>> type vector using the names (e.g., if the name starts with "author", then it
>> is of type 0, if the name starts with "thread", then it is of type 1).
>> Finally, assign the type vector to the "type" attribute (V(g)\$type <- types)
>> and you're ready.
>>
>> --
>> Tamas
>>
>>
>> _______________________________________________
>> igraph-help mailing list
>> address@hidden
>> http://lists.nongnu.org/mailman/listinfo/igraph-help
>
>
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--
Gabor Csardi <address@hidden>     UNIL DGM

```

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