Simple Data

Each HDF5 attribute or dataset has an associated dataspace which is either of type null, scalar or simple. The following overview shows you how to handle these different dataspace types:

null: You cannot read null dataspaces as they contain no data.
scalar: Provide a compatible scalar return type. To read the value of a scalar dataset of type int call dataset.Read<int>().
simple: Provide a compatible array return type. To read the value of a 2D dataset of type int call dataset.Read<int[,]>()

The following section shows you how to read 1D datasets of any datatype. All samples shown work for datasets as well as attributes.

// class: fixed-point

    var data = dataset.Read<int[]>();

// class: floating-point

    var data = dataset.Read<double[]>();

// class: string

    var data = dataset.Read<string[]>();

// class: bitfield

    [Flags]
    enum SystemStatus : ushort /* make sure the enum in HDF file is based on the same type */
    {
        MainValve_Open          = 0x0001,
        AuxValve_1_Open         = 0x0002,
        AuxValve_2_Open         = 0x0004,
        MainEngine_Ready        = 0x0008,
        FallbackEngine_Ready    = 0x0010
        // ...
    }

    var data = dataset.Read<SystemStatus[]>();
    var readyToLaunch = data[0].HasFlag(SystemStatus.MainValve_Open | SystemStatus.MainEngine_Ready);

// class: opaque

    var data = dataset.Read<MyOpaqueStruct[]>();

// class: compound

    /* option 1: faster (if no reference types are contained) */
    var data = dataset.Read<MyNonNullableStruct[]>();

    /* option 2: slower (useful to read unknown structs) */
    var data = dataset.Read<Dictionary<string, object>>();

// class: reference @ object reference

    var references = dataset.Read<NativeObjectReference1[]>();
    var firstRef = references.First();

    /* NOTE: Dereferencing would be quite fast if the object's name
     * was known. Instead, the library searches recursively for the  
     * object. Do not dereference using a parent (group) that contains
     * any circular soft links. Hard links are no problem.
     */

    /* option 1 (faster) */
    var firstObject = directParent.Get(firstRef);

    /* option 1 (slower, use if you don't know the objects parent) */
    var firstObject = root.Get(firstRef);

// class: reference @ region reference

    var references = dataset.Read<NativeRegionReference1[]>();
    var firstRef = references.First();
    var selection = root.Get(firstRef);
    var data = referencedDataset.Read<T>(fileSelection: selection);

// class: enumerated

    enum MyEnum : short /* make sure the enum in HDF file is based on the same type */
    {
        MyValue1 = 1,
        MyValue2 = 2,
        // ...
    }

    var data = dataset.Read<MyEnum[]>();

// class: variable length strings

    var data = dataset.Read<string[]>();

// class: variable length sequences

    var data = dataset.Read<T[][]>();

// class: array

    var data = dataset.Read<T[][]>;

// class: time
// -> not supported (reason: the HDF5 C lib itself does not fully support H5T_TIME)

Note

For more information about compound data, see section Compound Data.

Table of Contents

Simple Data

Note