Subset a neighbours list
The function subsets a neighbors list, retaining objects for which the subset argument vector is TRUE.
## S3 method for class 'nb' subset(x, subset, ...)
x |
an object of class |
subset |
logical expression |
... |
generic function pass-through |
The function returns an object of class nb with a list of
integer vectors containing neighbour region number ids (compacted to
run from 1:number of regions in subset).
Roger Bivand Roger.Bivand@nhh.no
columbus <- st_read(system.file("shapes/columbus.shp", package="spData")[1], quiet=TRUE)
col.gal.nb <- read.gal(system.file("weights/columbus.gal", package="spData")[1])
coords <- coordinates(as(columbus, "Spatial"))
plot(col.gal.nb, coords)
to.be.dropped <- c(31, 34, 36, 39, 42, 46)
text(coords[to.be.dropped,1], coords[to.be.dropped,2], labels=to.be.dropped,
pos=2, offset=0.3)
sub.col.gal.nb <- subset(col.gal.nb,
!(1:length(col.gal.nb) %in% to.be.dropped))
plot(sub.col.gal.nb, coords[-to.be.dropped,], col="red", add=TRUE)
which(!(attr(col.gal.nb, "region.id") %in%
attr(sub.col.gal.nb, "region.id")))Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.