Add easy way to iterate through every chunk of an array

[dstansby]

I am finding myself wanting to apply an operation (e.g., thresholding) on every chunk in an array. It would therefore be nice if there was an easy way to iterate through each chunk of the array.

Something like:

for i, chunk in enumerate(zarr_arr.all_chunks):
    zarr.all_chunks[i] = np.clip(chunk, min, max)

This is sort of similar to block indexing, but iterating over Array.blocks only iterates over the first axis of blocks, and gives you back all the chunks along the other axes.

[d-v-b]

something like this?

zarr-python/src/zarr/core/array.py

Line 893 in 4c3081c

def _iter_chunk_regions(

?

[dstansby]

Hard to tell just looking at the code, but from the docstring I think that sounds about right 😄

[dcherian]

Can we remake .blocks.__iter__ to be more like np.nditer instead?

[dstansby]

I think that would be quite a big braking API change, so probably worth creating a freshly named property or method?

[d-v-b]

i'm not a big fan of .blocks to be honest, i don't think it's a very intuitive API for something as simple as "access data chunk by chunk". i'm not saying we should remove it, but we should take the 2 -> 3 transition as an opportunity to think about whether there's a better way to do things