Extract.sparse3Darray: Extract or Replace Entries in a Sparse Array

In spatstat.sparse: Sparse Three-Dimensional Arrays and Linear Algebra Utilities

Extract or Replace Entries in a Sparse Array

Description

Extract or replace entries in a sparse three-dimensional array.

Usage

  ## S3 method for class 'sparse3Darray'
x[i, j, k, drop=TRUE, ...]
  ## S3 replacement method for class 'sparse3Darray'
x[i, j, k, ...] <- value

Arguments

x	Sparse three-dimensional array (object of class "sparse3Darray").
i,j,k	Subset indices for each dimension of the array. See Details.
value	Replacement value for the subset.
drop	Logical value indicating whether to return a lower-dimensional object (matrix or vector) when appropriate.
...	Ignored. This argument is required for compatibility with the generic function.

Details

These functions are defined for a sparse three-dimensional array x. They extract a designated subset of the array, or replace the values in the designated subset.

The function [.sparse3Darray is a method for the generic subset extraction operator [. The function [<-.sparse3Darray is a method for the generic subset replacement operator [<-.

These methods use the same indexing rules as the subset operator for full arrays:

• If i, j and k are integer vectors, the subset is the Cartesian product (i.e. all cells in the array identified by an entry of i, an entry of j and an entry of k).

• Some or all of the arguments i, j and k may be missing from the call; a missing index argument is interpreted as meaning that all possible values of that index are allowed.

• Arguments i, j and k may be logical vectors (with the value TRUE assigned to entries that should be included).

• Arguments i, j and k may be character vectors with entries matching the corresponding dimnames.

• Argument i may be an integer matrix with 3 columns (and the arguments j,k should be absent). Each row of the matrix contains the indices of one cell in the array.

If the designated subset lies within the array bounds, then the result of [ will be a sparse three-dimensional array, sparse matrix or sparse vector. If drop=FALSE the result will always be three-dimensional; if drop=TRUE (the default) the result will be reduced to two or one dimensions when appropriate.

If the designated subset does not lie within the array bounds, then the result of [ will be a full three-dimensional array, matrix or vector containing NA values at the positions that were outside the array bounds.

The result of [<- is always a sparse three-dimensional array. If the designated subset did not lie within the array bounds of x, then the array bounds will be extended (with a warning message).

Value

[.sparse3Darray returns either a sparse three-dimensional array (class "sparse3Darray"), a sparse matrix (class sparseMatrix in the Matrix package), a sparse vector (class sparseVector in the Matrix package), or in some cases a full array, matrix or vector.

[<-.sparse3Darray returns another sparse three-dimensional array.

Author(s)

\spatstatAuthors

.

See Also

sparse3Darray, methods.sparse3Darray.

Examples

  M <- sparse3Darray(i=1:4, j=sample(1:4, replace=TRUE),
                     k=c(1,2,1,2), x=1:4, dims=c(5,5,2))
  dimnames(M) <- list(letters[1:5], LETTERS[1:5], c("yes", "no"))
  M[ 3:4, , ]
  M[ 3:4, 2:4, ]
  M[ 4:3, 4:2, 1:2]
  M[, 3, ]

spatstat.sparse documentation built on Oct. 24, 2023, 9:08 a.m.