snapKrig (version 0.0.2)

[.sk: Extract a sk list element (single-bracket access)

Description

Copies the specified list element or grid point value

Usage

# S3 method for sk
[(x, i = NULL, j = NULL, drop = FALSE, ...)

Value

a list, vector, or matrix (see description)

Arguments

x

a sk object

i

column-vectorized index

j

index of layer (only for multi-layer x)

drop

ignored

...

ignored

Details

Behavior depends on the class of i. For character vectors this extracts the named list entries of x. For numeric, it accesses the vectorized grid data values. For multi-layer objects, a layer can be specified in j.

the default NULL for i and j is treated as numeric, and is shorthand for all indices. For example if x has a single-layer x[] returns all grid data in a vector. If x is multi-layer x[,1] all grid data from the first layer, and x[] returns all layers, as a matrix.

Examples

# define a sk list and extract two of its elements
g = sk_validate(list(gval=stats::rnorm(4^2), gdim=4, gres=0.5))
g[c('gdim', 'gres')]

# display all the grid data as a vector or a matrix
g[]
matrix(g[], dim(g))

# extract a particular grid point or a subset
g[1]
g[seq(5)]