R: Subset a neighbours list

subset.nb {spdep} | R Documentation

## Subset a neighbours list

### Description

The function subsets a neighbors list, retaining objects for which the subset argument vector is TRUE.

### Usage

    ## S3 method for class 'nb'
    subset(x, subset, ...)

### Arguments

`x` | an object of class `nb`
`subset` | logical expression
`...` | generic function pass-through

### Value

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).

### Author(s)

Roger Bivand Roger.Bivand@nhh.no

### See Also

`nb2listw`

### Examples

    example(columbus)
    coords <- coordinates(columbus)
    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")))

[Package spdep version 0.6-13 Index]