e1071 (version 1.3-1)

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)

Arguments

x

An object of class matrix.csr

y

A vector (either numeric or a factor)

file

The filename.

fac

If TRUE and y-values are stored in the file, the values are interpreted as factor levels.

ncol

Number of columns, detected automatically. Can be used to add empty columns (these are 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!")
  }