[R] Two problems
Agustin Lobo
alobo at ija.csic.es
Fri Apr 19 11:31:58 CEST 2002
On Thu, 18 Apr 2002, Ambrosini Alessandro wrote:
> Hello! Two questions:
>
> 1: I have to import a matrix of adjacency from a file of a software that is
> not R (for example "bloc notes" of Windows). The problem is that the matrix
> is not in the explicit form as
> 0 1 1
> 1 0 0
> 1 0 0
> but it is a scattered matrix where in each row there are two nodes that have
> a direct path.
> The matrix is
>
> a b
> a c
> b a
> c a
>
I would use table():
> d1 <- c("a","a","b","c")
> d2 <- c("b","c","a","a")
> table(d1,d2)
d2
d1 a b c
a 0 1 1
b 1 0 0
c 1 0 0
But is this not a very unefficient way of storing adjacencies?
Agus
Dr. Agustin Lobo
Instituto de Ciencias de la Tierra (CSIC)
Lluis Sole Sabaris s/n
08028 Barcelona SPAIN
tel 34 93409 5410
fax 34 93411 0012
alobo at ija.csic.es
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