e1071 (version 1.6-2)

read.matrix.csr: Read/Write Sparse Data

Description

reads and writes a file in sparse data format.

Usage

read.matrix.csr(file, fac = TRUE, ncol = NULL)
write.matrix.csr(x, file = "out.dat", y = NULL, fac = TRUE)

Arguments

x

An object of class matrix.csr

y

A vector (either numeric or a factor)

file

The filename.

fac

If TRUE, the y-values (if any) are interpreted as factor levels.

ncol

Number of columns, detected automatically. Can be used to add empty columns (possibly not stored in the sparse format).

Value

• If the data file includes no y variable, read.matrix.csr returns an object of class matrix.csr, else a list with components:
• x
  object of class matrix.csr
• y
  vector of numeric values or factor levels, depending on fac.

See Also

matrix.csr

Examples

library(methods)
if (require(SparseM)) {
    data(iris)
    x <- as.matrix(iris[,1:4])
    y <- iris[,5]
    xs <- as.matrix.csr(x)
    write.matrix.csr(xs, y = y, file = "iris.dat")
    xs2 <- read.matrix.csr("iris.dat")$x
    if (!all(as.matrix(xs) == as.matrix(xs2)))
        stop("Error: objects are not equal!")
}