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)

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)

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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