@ptrblck
Thanks, so the code I wrote will not work because of memory right??
Then, Should I use the pandas load method when I define dataset class?
class loader(Dataset):
    def __init__():
        df = pd.DataFrame(np.random.rand(100, 1))
        df.to_hdf('file.h5', 'df', format='table')
        pd.read_hdf('file.h5', start=0, stop=1)

like this?