MATLAB Programming

Hierarchical Data Format (HDF5) Files
• Name of an existing data set or attribute,orthenameyouwanttoassign
to a new data set or attribute. To learn how to determine the name of data
sets in an existing HDF5 file, see “Determining the Contents of an HDF5
File” on page 7-12.
• Data or metadata you want to write to the file. hdf5write converts
MATLAB data types to the appropriate HDF5 data type automatically.
For nonatomic data types, you can also create HDF5 objects to represent
the data.
This example creates a 5-by-5 array of uint8 values and then writes the
array to an HDF5 file. By default, hdf5write overwrites the file, if it already
exists. The example specifies an hdf5write mode option to append data to
existing file.
1 Create a MATLAB variable in the workspace. This example creates a
5-by-5 array of uint8 values.
testdata = uint8(magic(5))
2 Write the data to an HDF5 file. As arguments to hdf5read, theexample
specifiesthenameyouwanttoassigntotheHDF5file,thenameyouwant
to assign to the data set, and the MATLAB variable.
hdf5write('myfile.h5', '/dataset1', testdata)
To add data to an existing file, you must use the 'writemode' option,
specifying the'append' value. The file must already exist and it cannot
already contain a data set with the same name
hdf5write('myfile.h5', '/dataset12', testdata,'writemode','append')
If you are writing simple data sets, such as scalars, strings, or a simple
compound data types, you can just pass the data directly to hdf5write; this
function automatically maps the MATLAB data types to appropriate HDF5
data types. However, if your data is a complex data set, you might need to
use one of the predefined MATLAB HDF5 objects to pass the data to the
hdf5write function. The HDF5 objects are designed for situations where the
mapping between MATLAB and HDF5 types is ambiguous.
For example, when passed a cell array of strings, the hdf5write function
writes a data set made up of strings, not a data set of arrays containing
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