H5 Objects

Contents

• H5 File

• H5 Group

• H5 Dataset

• H5 Dataspace

• H5Attribute

• H5 Type

• H5 Reference

Description

H5 objects have some accessible properties. All the properties name are case insensitive (except for the path or objects names).

H5 File

The following properties can be accessed:

• name: the filename;

• size: the file size;

• version: the HDF5 library version;

• root: the root group "/".

x = [1 2;3 4];
save(TMPDIR + "/x.sod", "x");
a = h5open(TMPDIR + "/x.sod");

// a is a file
h5isFile(a)

// Access to the properties
a.name, a.size, a.version, a.root

// Open the dataset x
a("/x")

// Free all the resources
h5close(a);

H5 Group

The following properties can be accessed:

• attributes: the attributes names;

• groups: the subgroups names;

• datasets: the datasets names;

• types: the types names;

• externals: the external links names;

• softs: the soft links names;

• danglings: the dangling links names;

• hards: the hard links names;

• links: the links names and types;

• name: the group name;

• path: the group path.

x = [1 2;3 4];
save(TMPDIR + "/x.sod", "x");
a = h5open(TMPDIR + "/x.sod");
root = a.root;

// root is a group
h5isGroup(root)

// Access to the properties
root.name, root.path, root.datasets, root.attributes

// Open the dataset x
dset_x = root.x

// Free all the resources
h5close(a);

H5 Dataset

The following properties can be accessed:

• attributes: the attributes names;

• type: the dataset type;

• dataspace: the dataset space;

• data: the dataset data;

• name: the group name;

• path: the group path.

x = [1 2;3 4];
save(TMPDIR + "/x.sod", "x");
a = h5open(TMPDIR + "/x.sod");
dset_x = a.root.x;

// dset_x is a dataset
h5isSet(dset_x)

// Access to the properties
dset_x.attributes, dset_x.type, dset_x.dataspace, dset_x.data

// Open the attribute x
attr_x = dset_x.SCILAB_Class

// Free all the resources
h5close(a);

H5 Dataspace

The following properties can be accessed:

• dims: the dataspace dimensions;

• extents: the dataspace max dimensions;

• type: the dataspace type: "scalar", "simple" or "null";

• name: the parent name.

• path: the parent path.

x = [1 2;3 4];
save(TMPDIR + "/x.sod", "x");
a = h5open(TMPDIR + "/x.sod");
dspace_x = a.root.x.dataspace;

// dspace_x is a space
h5isSpace(dspace_x)

// Access to the properties
dspace_x.dims, dspace_x.extents, dspace_x.type

// Free all the resources
h5close(a);

H5 Attribute

The following properties can be accessed:

• type: the attribute type;

• dataspace: the attribute dataspace;

• data: the attribute data;

• name: the attribute name.

• path: the parent path.

x = [1 2;3 4];
save(TMPDIR + "/x.sod", "x");
a = h5open(TMPDIR + "/x.sod");
attr_x = a.root.x.SCILAB_Class;

// attr_x is an attribute
h5isAttr(attr_x)

// Access to the properties
attr_x.type, attr_x.dataspace, attr_x.data

// Free all the resources
h5close(a);

H5 Type

The following properties can be accessed:

• class: the type class;

• type: the type name;

• size: the size in bytes;

• nativetype: the native type associated with this type;

• nativesize: the size of the native type.

• name: the parent name.

• path: the parent path.

x = [1 2;3 4];
save(TMPDIR + "/x.sod", "x");
a = h5open(TMPDIR + "/x.sod");
type_x = a.root.x.type;

// type_x is a type
h5isType(type_x)

// Access to the properties
type_x.class, type_x.type, type_x.size, type_x.nativetype, type_x.nativesize,

// Free all the resources
h5close(a);

H5 Reference

H5 Reference object wrap an hypermatrix object where elements are a reference to an H5 object.

x = list([1 2;3 4], "Hello", uint32(123));
save(TMPDIR + "/x.sod", "x");
a = h5open(TMPDIR + "/x.sod");
dims_x = a.root.x.dataspace.dims
ref_x = a.root.x.data;

// ref_x is a reference
h5isRef(ref_x)

// Get the 3 elements
x1 = ref_x(1), x2 = ref_x(2), x3 = ref_x(3)

// Get the data
x1.data, x2.data, x3.data

// Free all the resources
h5close(a);

See also

• h5attr — Create an attribute
• h5close — Close a HDF5 object
• h5cp — Copy an object
• h5dataset — Create a dataset and write the data
• h5dump — Dump the content of an H5 object on the standard output stream
• h5exists — Test the existence of named object
• h5flush — Flush all the buffers associated with a file
• h5get — Get a named object
• h5group — Create a group
• h5isAttr — Check if the HDF5 object is an attribute
• h5isFile — Check if the HDF5 object is a file
• h5isGroup — Check if the HDF5 object is a group
• h5isRef — Check if the HDF5 object is a reference object
• h5isSet — Check if the HDF5 object is a dataset
• h5isSpace — Check if the HDF5 object is a dataspace
• h5isType — Check if the HDF5 object is a type
• h5label — Label a dataset
• h5ln — Link an object to another one
• h5ls — List the content of an HDF5 object (group or dataset)
• h5mount — Mount a file on a group
• h5mv — Move an object
• h5open — Open an HDF5 file
• h5read — Read the data of an HDF5 attribute
• h5rm — Remove elements from an HDF5 file
• h5umount — Unmount a previously mounted file.
• h5write — Create a dataset (if it does not exist) and write the data
• h5writeattr — Write an attribute in a group or a dataset

History