Hi,

Maybe you should convert your nb object into a matrix using nb2mat then use
reshape package?

library(reshape)

df<-as.data.frame(nb.mat)

df$id<-row.names(df)

mdata<-melt(df,id="id")

then subset your data for which mdata$value > 0


2011/3/21 Kevin Ringelman <kmringelman@ucdavis.edu>

> Thanks for your help Roger.  I have a couple more questions.
>
> print.default(nb) shows me what I'm looking for: for each region, I see the
> regions that are within my distance band.  For example:
>
> [[1]]
>  [1]   2  10  11  15  17  18  19  32  40 554
>
> [[2]]
>  [1]   1  15  17  21  33  34 426 511 554 557
>
> I want to make this information into a table, with the focal regions as
> column 1, and the region IDs of it's neighbors as column 2 (similar to
> neighbor analysis output in ArcGIS).  Continuing the example from above:
> 1       2
> 1       10
> 1       11
> 1       15
> 1       17
> (etc.)
>
> Even after I nuke the nb class
> U <- unclass(nb)
> I still can't access or manipulate the data...it doesn't appear as an
> attribute
> attribute(U)
>
> Any suggestions?
>
>
>
>
>
> -----Original Message-----
> From: Roger Bivand [mailto:Roger.Bivand@nhh.no]
> Sent: Saturday, March 05, 2011 10:03 AM
> To: Kevin Ringelman
> Cc: r-sig-geo@r-project.org
> Subject: Re: [R-sig-Geo] spdep: show neighbors from "dnearneigh"
>
> On Fri, 4 Mar 2011, Kevin Ringelman wrote:
>
> > I am having trouble viewing the list of neighbors ("regions IDs") after
> > created a nb object using the "dnearneigh" function in spdep.  I only
> seem
> > to get a summary (with # regions, # non-zero links, etc.).  This nb
> object
> > also doesn't take well to being converted to another type of object, or
> > exported from R.  How I view the list of neighbors?
> >
>
> In S and R, objects with a class attribute, such as "nb" objects, may have
> display methods specific to the class. If you just say:
>
> > nb
>
> then this is expanded internally to print(nb), and since nb is an object
> of class "nb", the print.nb() method is chosen. If you want the default
> print method, call it as print.default(nb). Conversion of objects of one
> class to another class may be done by coercion where coercion methods are
> provided. No such methods are available for nb objects. There are
> functions to do things like this, but not methods. For example, to make an
> nb object into a row-standardised matrix, you might do:
>
> > Wmat <- nb2mat(nb, style="W")
>
> but you should avoid this if your number of observations is large. To make
> a sparse matrix, several steps are required:
>
> > lw <- nb2listw(nb, style="W")
> > spWmat <- as(as_dgRMatrix_listw(lw), "CsparseMatrix")
>
> using the nb2listw() and (ugly name) as_dgRMatrix_listw() functions, and
> coercion from one representation to another using new-style classes
> defined in the Matrix package.
>
> >
> >
> > Some additional background: I'm identifying all neighboring bird nests
> > within 100m of each nest.  For this particular analysis, I ultimately
> want
> > to calculate the average vegetation height of neighboring nests to
> compare
> > with the focal nest.  This will involve generating a list of neighbors,
> and
> > merging that list with my other data.
> >
>
> Note that an nb object is a list - to nuke the class, do:
>
> > class(nb) <- NULL
>
> which lets you call print.default(), but to get at the attribute you want,
> just do:
>
> > attr(nb, "region.id")
>
> to call print.default on the character vector it contains.
>
> Hope this clarifies,
>
> Roger
>
> >
> >
> > Thanks,
> >
> > Kevin
> >
> >
> >       [[alternative HTML version deleted]]
> >
> > _______________________________________________
> > R-sig-Geo mailing list
> > R-sig-Geo@r-project.org
> > https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> >
>
> --
> Roger Bivand
> Economic Geography Section, Department of Economics, Norwegian School of
> Economics and Business Administration, Helleveien 30, N-5045 Bergen,
> Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
> e-mail: Roger.Bivand@nhh.no
>
> _______________________________________________
> R-sig-Geo mailing list
> R-sig-Geo@r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>

	[[alternative HTML version deleted]]

