write_myfile.py

import h5py
import os

myfile = 'myfile.hdf5'

print "remove %s" % myfile
if os.path.exists(myfile):
    os.remove(myfile)

print "write to %s" % myfile
f = h5py.File(myfile, 'w')
dset = f.create_dataset("MyDataset", (100, 100), 'i')
dset[...] = 42

import numpy as np
arr = np.ones((2,3), '=i4')
dset = f.create_dataset('AnotherDataset', data=arr)

subgroup = f.create_group("SubGroup")
dset2 = subgroup.create_dataset('MyOtherDataset', (4,5), '=f8')

dset2 = np.arange( 4*5, dtype=float ).reshape(4,5)

f.close()