write.mat-methods: Write Matlab file

In rmatio: Read and Write 'Matlab' Files

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 signature 'list'
write.mat(object, filename = NULL, compression = TRUE, version = c("MAT5"))

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.

Details

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

Value

invisible NULL

Note

• A vector is saved as a 1 x length array

• Support for writing a sparse matrix of type 'dgCMatrix' or 'lgCMatrix' to file

Author(s)

Stefan Widgren

Examples

## Not run: 
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)

## End(Not run)

rmatio documentation built on May 29, 2024, 10:34 a.m.