R: Read/Write Sparse Data

read.matrix.csr {e1071} | R Documentation

## 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`.

### Author(s)

David Meyer
David.Meyer@R-project.org

### See Also

`matrix.csr`

### Examples

    ## Not run:
    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!")
    }

    ## End(Not run)

[Package e1071 version 1.7-4 Index]