H5D.write

Write data to HDF5 dataset

Syntax

H5D.write(dataset_id,mem_type_id,mem_space_id,file_space_id,plist_id,buf)

Description

H5D.write(dataset_id,mem_type_id,mem_space_id,file_space_id,plist_id,buf) writes the dataset specified by dataset_id from the application memory buffer buf into the file. plist_id specifies the data transfer properties. mem_type_id identifies the memory datatype of the dataset. mem_space_id and file_space_id define the part of the dataset to write. The memory datatype should usually be 'H5ML_DEFAULT', which specifies that MATLAB® should determine the appropriate memory datatype.

Note

The HDF5 library uses C-style ordering for multidimensional arrays, while MATLAB uses FORTRAN-style ordering. Please consult "Using the MATLAB Low-Level HDF5 Functions" in the MATLAB documentation for more information.

Examples

Write to the entire 36-by-19 /g4/world example dataset.

srcFile = fullfile(matlabroot,'toolbox','matlab','demos','example.h5');
copyfile(srcFile,'myfile.h5');
fileattrib('myfile.h5','+w');
plist = 'H5P_DEFAULT';
fid = H5F.open('myfile.h5','H5F_ACC_RDWR',plist);
dset_id = H5D.open(fid,'/g4/world');
dims = [36 19];
data = rand(dims);
H5D.write(dset_id,'H5ML_DEFAULT','H5S_ALL','H5S_ALL',plist,data);
H5D.close(dset_id);
H5F.close(fid);

Write to the entire two-element /g3/VLstring dataset.

srcFile = fullfile(matlabroot,'toolbox','matlab','demos','example.h5');
copyfile(srcFile,'myfile.h5');
fileattrib('myfile.h5','+w');
h5disp('myfile.h5','/g3/VLstring');
plist = 'H5P_DEFAULT';
fid = H5F.open('myfile.h5','H5F_ACC_RDWR',plist);
dset_id = H5D.open(fid,'/g3/VLstring');
data = {'dogs'; 'dogs and cats'};
H5D.write(dset_id,'H5ML_DEFAULT','H5S_ALL','H5S_ALL',plist,data);
H5D.close(dset_id);
H5F.close(fid);
data_out = h5read('myfile.h5','/g3/VLstring');

Write a 10-by-5 block of data to the location starting at row index 15 and column index 5 of the same dataset. Recall that indexing is zero-based.

srcFile = fullfile(matlabroot,'toolbox','matlab','demos','example.h5');
copyfile(srcFile,'myfile.h5');
fileattrib('myfile.h5','+w');
plist = 'H5P_DEFAULT';
fid = H5F.open('myfile.h5','H5F_ACC_RDWR',plist);
dset_id = H5D.open(fid,'/g4/world');
start = [15 5];
h5_start = fliplr(start);
block = [10 5];
h5_block = fliplr(block);
mem_space_id = H5S.create_simple(2,h5_block,[]);
file_space_id = H5D.get_space(dset_id);
H5S.select_hyperslab(file_space_id,'H5S_SELECT_SET',h5_start,[],[],h5_block);
data = rand(block);
H5D.write(dset_id,'H5ML_DEFAULT',mem_space_id,file_space_id,plist,data);
H5D.close(dset_id);
H5F.close(fid);

Limitations

  • You can write to variable length datasets only if the datatype class of the dataset is one of the following:

    • H5T_INTEGER

    • H5T_FLOAT

    • H5T_STRING with variable length or a fixed length of 1.

See Also

MATLAB Documentation

Support