R help - Feb 2012 - Neighbour List to Matrix

Hi everybody!I'm a new user of R. I've been having a look to sotored
mails in list, but I've been not able to find one suiting to my need. The
issue is I have a neighbour list in a TXT file, just as lists generated by
social network softwares (f.i. Pajek), where you get Field1, Field2, Value. In
my case, list follow the next way:ID1	IDP2	SUMVAL1	56	0.0659358951	900
0.0441101851	1409	0.1963141973	4	0.0713203883	83	0.0162695643	529	0.0113592393
883	0.0122425333	1242	0.0165589244	3	0.0043070244	7	0.0046998214	16	0.0047351125
7	0.0103249265	16	0.0112505045	498	0.0097098585	502	0.0047757495	508	0.031411560
The question is, how can I convert this list into a matrix? I think is good to
know that list contain more than 600000 rows with around 14000 nodes
(participants). If it's possible I would like to know all necessary stetps
to do this. This is: load the TXT file, create the matrix through data contained
in it, and finally to export to CSV or TXT file. Any idea or suggestion will be
wellcome!Thank you very much in advance.AJ
 		 	   		  
	[[alternative HTML version deleted]]

You might want to post a better example of what your data looks like.
In the email, it is hard to tell how to split the data into rows that
can be read with three fields since it looks like the data is composed
of pairs of numbers.

On Fri, Feb 17, 2012 at 7:42 AM, A J <anxusgo at hotmail.com>
wrote:
>
> Hi everybody!I'm a new user of R. I've been having a look to
sotored mails in list, but I've been not able to find one suiting to my
need. The issue is I have a neighbour list in a TXT file, just as lists
generated by social network softwares (f.i. Pajek), where you get Field1,
Field2, Value. In my case, list follow the next way:ID1 ?IDP2 ? ?SUMVAL1 56 ? ?
?0.0659358951 ? ?900 ? ? 0.0441101851 ? ?1409 ? ?0.1963141973 ? ?4 ? ? ?
0.0713203883 ? ?83 ? ? ?0.0162695643 ? ?529 ? ? 0.0113592393 ? ?883 ? ?
0.0122425333 ? ?1242 ? ?0.0165589244 ? ?3 ? ? ? 0.0043070244 ? ?7 ? ? ?
0.0046998214 ? ?16 ? ? ?0.0047351125 ? ?7 ? ? ? 0.0103249265 ? ?16 ? ?
?0.0112505045 ? ?498 ? ? 0.0097098585 ? ?502 ? ? 0.0047757495 ? ?508 ? ?
0.031411560
> The question is, how can I convert this list into a matrix? I think is good
to know that list contain more than 600000 rows with around 14000 nodes
(participants). If it's possible I would like to know all necessary stetps
to do this. This is: load the TXT file, create the matrix through data contained
in it, and finally to export to CSV or TXT file. Any idea or suggestion will be
wellcome!Thank you very much in advance.AJ
>
> ? ? ? ?[[alternative HTML version deleted]]
>
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-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.

I think is good to know that list contain more than 600000 rows with
around 14000 nodes (participants).

?read.table may be unreliable for large matrices and with 14/600
you'll end up with many NA's. You might do better with

nbrs<-
scan('nbrs.txt',skip=1,what=list('integer','integer',double(0)))
names(nbrs) <- c('c1','c2','c3')
xtabs(c3~c1+c2,nbrs,sparse=T)

# returns
4 x 9 sparse Matrix of class "dgCMatrix"
      1     2     3     4     5     6     7     8     9
1 .     0.065 0.044 .     .     .     .     .     .
3 0.071 .     .     0.016 0.011 .     .     .     .
4 .     .     0.004 .     .     .     0.004 .     0.004
5 .     .     .     0.010 .     0.011 .     0.009 0.004

Cheers