henrydayhall / lazy_ops

Lazy transposing and slicing of h5py and Zarr Datasets

lazy_ops

Lazy transposing and slicing of h5py Datasets and zarr arrays

Installation

$ pip install lazy_ops

Usage:

from lazy_ops import DatasetView

# h5py #
import h5py
dsetview = DatasetView(dataset) # dataset is an instance of h5py.Dataset
view1 = dsetview.lazy_slice[1:40:2,:,0:50:5].lazy_transpose([2,0,1]).lazy_slice[8,5:10]

# zarr #
import zarr
zarrview = DatasetView(zarray) # dataset is an instance of zarr.core.Array
view1 = zview.lazy_slice[1:10:2,:,5:10].lazy_transpose([0,2,1]).lazy_slice[0:3,1:4]

# reading from view on either h5py or zarr
A = view1[:]          # Brackets on DataSetView call the h5py or zarr slicing method, returning the data
B = view1.dsetread()  # same as view1[:]

# iterating on either h5yy or zarr
for ib in view.lazy_iter(axis=1):
    print(ib[0])