Reads a MAT file structure from a connection or a file.
 Both the MAT version 4 and MAT version 5 file formats are
 supported. The implementation is based on [1-5].
 Note: Do not mix up version numbers for the MATLAB software and
 the MATLAB file formats.

readMat

Methods readMat() and writeMat() for reading and writing MAT files.  For users with MATLAB v6 or newer installed (either locally or on a remote host), the package also provides methods for controlling MATLAB (trademark) via R and sending and retrieving data between R and MATLAB.

Henrik Bengtsson

R.matlab

Read and Write MAT Files and Call MATLAB from Within R

Andy Jacobson

Jason Riedy

readMat function

Reads a MAT file structure from a connection or a file — readMat

<dl>

 <dt>con</dt>
<dd>Binary <code><a href='https://rdrr.io/r/base/connections.html'>connection</a></code> from which the MAT file structure
 should be read.
 If a <code><a href='https://rdrr.io/r/base/character.html'>character</a></code> string, it is interpreted as filename, which then
 will be opened (and closed afterwards).
 If a <code><a href='https://rdrr.io/r/base/raw.html'>raw</a></code> <code><a href='https://rdrr.io/r/base/vector.html'>vector</a></code>, it will be read via as a raw binary <code><a href='https://rdrr.io/r/base/connections.html'>connection</a></code>.</dd>

 <dt>maxLength</dt>
<dd>The maximum number of bytes to be read from the input
 stream, which should be equal to the length of the MAT file structure.
 If <code>NULL</code>, data will be read until End Of File has been reached.</dd>

 <dt>fixNames</dt>
<dd>If <code><a href='https://rdrr.io/r/base/logical.html'>TRUE</a></code>, underscores within names of MATLAB variables
 and fields are converted to periods.</dd>

 <dt>drop</dt>
<dd>A <code><a href='https://rdrr.io/r/base/character.html'>character</a></code> <code><a href='https://rdrr.io/r/base/vector.html'>vector</a></code> specifying cases when one or more dimensions
 of elements should be dropped in order to decrease the amount of "nestedness"
 of the returned data structure. This only applies to the MAT v5 file format.</dd>

 <dt>sparseMatrixClass</dt>
<dd>If <code>"matrix"</code>, a sparse matrix is expanded to
 a regular <code><a href='https://rdrr.io/r/base/matrix.html'>matrix</a></code>. If either <code>"Matrix"</code> (default) or <code>"SparseM"</code>,
 the sparse matrix representation by the package of the same name will be used.
 These packages are only loaded if the a sparse matrix is read.</dd>

 <dt>verbose</dt>
<dd>Either a <code><a href='https://rdrr.io/r/base/logical.html'>logical</a></code>, a <code><a href='https://rdrr.io/r/base/numeric.html'>numeric</a></code>, or a <code>Verbose</code>
 object specifying how much verbose/debug information is written to
 standard output. If a Verbose object, how detailed the information is
 is specified by the threshold level of the object. If a numeric, the
 value is used to set the threshold of a new Verbose object. If <code><a href='https://rdrr.io/r/base/logical.html'>TRUE</a></code>,
 the threshold is set to -1 (minimal). If <code><a href='https://rdrr.io/r/base/logical.html'>FALSE</a></code>, no output is written.</dd>

 <dt>...</dt>
<dd>Not used.</dd>

</dl>

Arguments

This function uses a MAT file parser implemented completely using
 pure R. For MAT files containing large vectorized objects, for instance
 long vectors and large matrices, the R implementation is indeed fast
 enough because it can read and parse each such objects in one go.
On the other hand, for MAT files containing a large number of small
 objects, e.g. a large number of cell structures, there will be a
 significant slowdown, because each of the small objects has to be
 parsed individually.
 In such cases, if possible, try to (re)save the data in MATLAB
 using larger ("more vectorized") objects.

Speed performance

For the MAT v5 format, cell structures are read into
 R as a <code><a href='https://rdrr.io/r/base/list.html'>list</a></code> structure.

MAT cell structures

Recent versions of MATLAB store some strings using Unicode
 encodings (<code>miUTF8</code>, <code>miUTF16</code>, <code>miUTF32</code>), which are
 read as UTF-8. UTF-16 surrogate pairs (Unicode code points above
 <code>0xFFFF</code>) are not reassembled.

Unicode strings

From MATLAB v7, compressed MAT version 5 files are used by
 default [3-5], which is supported by this function.
If for some reason it fails, use <code>save -V6</code> in MATLAB to write
 non-compressed MAT v5 files (sic!).

Reading compressed MAT files

MAT v7.3 files, saved using for instance <code>save('foo.mat', '-v7.3')</code>,
 stores the data in the Hierarchical Data Format (HDF5) [6, 7], which
 is a format not supported by this function/package.
 However, there exist other R packages that can parse HDF5, e.g.
 CRAN package h5 and Bioconductor package rhdf5.

About MAT files saved in MATLAB using '-v7.3'

Reads a MAT file structure from an input stream, either until End of File
 is detected or until <code>maxLength</code> bytes has been read.
 Using <code>maxLength</code> it is possible to read MAT file structure over
 socket connections and other non-terminating input streams. In such cases
 the <code>maxLength</code> has to be communicated before sending the actual
 MAT file structure.

Reading MAT file structures input streams

Henrik Bengtsson.
 The internal MAT v4 reader was written by
 Andy Jacobson (Princeton University).
 Support for reading sparse matrices, UTF-encoded strings and
 compressed files, was contributed by Jason Riedy (UC Berkeley).

readMat: Reads a MAT file structure from a connection or a file

Description

Usage

Arguments

Value

References

See Also

Examples