Read Matlab file

Description

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

Usage

read.mat(filename)

Arguments

Details

Reads the values in a mat-file and stores them in a list.

Value

A list with the variables read.

Note

• A sparse complex matrix is read as a dense complex matrix.

• A sparse logical matrix is read as a 'lgCMatrix'

• A sparse matrix is read as a 'dgCMatrix'

• A matrix of dimension 1 x n or n x 1 is read as a vector

• A structure is read as a named list with fields.

• A cell array is read as an unnamed list with cell data

• A function class type is read as NULL and gives a warning.

See Also

See write.mat for more details and examples.

Examples

## Read a version 4 MAT file with little-endian byte ordering
filename <- system.file("extdata/matio_test_cases_v4_le.mat",
                        package = "rmatio")
m <- read.mat(filename)

## View content
str(m)

## Read a version 4 MAT file with big-endian byte ordering.
filename <- system.file("extdata/matio_test_cases_v4_be.mat",
                        package = "rmatio")
m <- read.mat(filename)

## View content
str(m)

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

## View content
str(m)

rmatio: reading and writing Matlab MAT files from R

Description

Reading and writing Matlab MAT files from R

Details

rmatio supports reading MAT version 4, MAT version 5 and MAT compressed version 5.

rmatio can write version 5 MAT files and version 5 files with variable compression.

References

• Christopher C. Hulbert, MATIO User Manual for version 1.5.2.
  https://sourceforge.net/projects/matio/files/matio/1.5.2/ matio_user_guide.pdf/download

• The MathWorks Inc., MATLAB - MAT-File Format, version R2013b, September 2013.
  https://www.mathworks.com/help/pdf_doc/matlab/matfile_format.pdf

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

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)