spam (version 0.20-3)

triplet: Transform a spam format to triplets

Description

Returns a list containing the indices and elements of a spam object.

Usage

triplet(x, tri=FALSE)

Arguments

x

sparse matrix of class spam or a matrix.

tri

Boolean indicating whether to create individual row and column indices vectors.

Value

• A list with elements
• indices
  a by two matrix containing the indices if tri=FALSE.
• i,j
  vectors containing the row and column indices if tri=TRUE.
• values
  a vector containing the matrix elements

Details

The elements are row (column) first if x is a spam object (matrix).

See Also

spam.list for the inverse operation and foreign for other transformations.

Examples

x <- diag.spam(1:4)
x[2,3] <- 5
triplet(x)
all.equal( spam(triplet(x, tri=TRUE)), x)