`card.Rd`

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

`card(nb)`

- nb
a neighbours list object of class

`nb`

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

“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.

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.

```
col.gal.nb <- read.gal(system.file("weights/columbus.gal", package="spData")[1])
table(card(col.gal.nb))
#>
#> 2 3 4 5 6 7 8 9 10
#> 7 7 13 4 9 6 1 1 1
```