rmatio (version 0.19.0)

write.mat: Write Matlab file

Description

Writes the values in a list to a mat-file.

Usage

write.mat(object, filename = NULL, compression = TRUE, version = c("MAT5"))
# S4 method for list
write.mat(object, filename = NULL, compression = TRUE, version = c("MAT5"))

Value

invisible NULL

Arguments

object

The object to write.

filename

The MAT file to write.

compression

Use compression when writing variables. Defaults to TRUE.

version

MAT file version to create. Currently only support for Matlab level-5 file (MAT5) from rmatio package.

Author

Stefan Widgren

Details

Writes the values in the list to a mat-file. All values in the list must have unique names.

Examples

if (FALSE) {
library(Matrix)
filename <- tempfile(fileext = ".mat")

## Example how to read and write an integer vector with rmatio
write.mat(list(a = 1:5), filename = filename)
a <- as.integer(read.mat(filename)[["a"]])

stopifnot(identical(a, 1:5))

unlink(filename)

## Read a compressed version 5 MAT file
m <- read.mat(system.file("extdata/matio_test_cases_compressed_le.mat",
                          package = "rmatio"))

## Write an uncompressed version 5 MAT file
write.mat(m, filename = "test-uncompressed.mat", compression = FALSE,
          version = "MAT5")

## Write a compressed version 5 MAT file
write.mat(m, filename = "test-compressed.mat", compression = TRUE,
          version = "MAT5")

## Check that the content of the files are identical
identical(read.mat("test-uncompressed.mat"),
          read.mat("test-compressed.mat"))

unlink("test-uncompressed.mat")
unlink("test-compressed.mat")

## Example how to read and write a S4 class with rmatio
## Create 'DemoS4Mat' class
setClass("DemoS4Mat",
         representation(a = "dgCMatrix",
                        b = "integer",
                        c = "matrix",
                        d = "numeric"))

## Create a function to coerce a 'DemoS4Mat' object to a list.
setAs(from = "DemoS4Mat",
      to = "list",
      def = function(from) {
        return(list(a = from@a,
                    b = from@b,
                    c = from@c,
                    d = from@d))
      }
)

## Create a function to coerce a list to a 'DemoS4Mat' object.
setAs(from = "list",
      to = "DemoS4Mat",
      def = function(from) {
        new("DemoS4Mat",
            a = from[["a"]],
            b = as.integer(from[["b"]]),
            c = from[["c"]],
            d = from[["d"]])
      }
)

## Define a method to write a 'DemoS4Mat' object to a MAT file.
setMethod("write.mat",
          signature(object = "DemoS4Mat"),
          function(object,
                   filename,
                   compression,
                   version) {
            ## Coerce the 'DemoS4Mat' object to a list and
            ## call 'rmatio' 'write.mat' with the list.
            write.mat(as(object, "list"),
                      filename,
                      compression,
                      version)
          }
)

## Create a new 'DemoS4Mat' object
demoS4mat <- new("DemoS4Mat",
                 a = Matrix(c(0, 0, 0, 0, 0, 0, 1, 0, 0,
                              0, 0, 0, 0, 0, 0, 0, 1, 0,
                              0, 0, 0, 0, 0, 0, 0, 0, 1),
                              nrow = 3,
                              ncol = 9,
                              byrow = TRUE,
                              sparse = TRUE),
                 b = 1:5,
                 c = matrix(as.numeric(1:9), nrow = 3),
                 d = c(6.0, 7.0, 8.0))

## Write to MAT file
write.mat(demoS4mat, filename)

## Read the MAT file
demoS4mat_2 <- as(read.mat(filename), "DemoS4Mat")

## Check result
stopifnot(identical(demoS4mat, demoS4mat_2))

unlink(filename)
}