card function

Cardinalities for neighbours lists

The function tallies the numbers of neighbours of regions in the neighbours list.

card(nb)

Arguments

• nb: a neighbours list object of class nb

Returns

An integer vector of the numbers of neighbours of regions in the neighbours list.

Details

nb objects are stored as lists of integer vectors, where the vectors contain either the indices in the range 1:n for n as length(nb) of the neighbours of region i, or as.integer(0) to signal no neighbours. The function card(nb) is used to extract the numbers of neighbours from the nb object.

References

Bivand R, Pebesma EJ, Gomez-Rubio V, (2008) Applied Spatial Data Analysis with R, Springer, New York, pp. 239-251; Bivand R, Portnov B, (2004) Exploring spatial data analysis techniques using R: the case of observations with no neighbours. In: Anselin L, Florax R, Rey S, (eds.), Advances in Spatial Econometrics, Methodology, Tools and Applications. Berlin: Springer-Verlag, pp. 121-142, tools:::Rd_expr_doi("10.1007/978-3-662-05617-2_6") .

Author(s)

Roger Bivand Roger.Bivand@nhh.no

See Also

summary.nb

Examples

col.gal.nb <- read.gal(system.file("weights/columbus.gal", package="spData")[1])
table(card(col.gal.nb))