Dear all, First of all, thanks to the answers to my previous post about this package. I am looking for the best way to copy (efficiently) hdf5.datasets objects. To be more precise, I have a large array that is a dataset reference. I would like to make a copy of this one, the copy being a dataset reference to an another dataset. I suspect that creating a new dataset then looping through the elements will be rather slow... but my inexperience with the package does not let me think of an alternative way... ...any suggestion ? L.