Read/Write Sparse Data

reads and writes a file in sparse data format.

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.

Author

David Meyer
David.Meyer@R-project.org

See also

matrix.csr

Examples

if (FALSE) { # \dontrun{
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!")
}
} # }