what to do when a variable is sliced with an all False Boolean index array?

[jswhit]

Current behavior:

1. for a 1D variable an empty array is returned
2. for multi-dim variables an opaque exception is raised.
3. for numpy arrays, an empty array is always returned

Two potential solutions:

1. PR Added more descriptive error message if indexing with all False bool … #1197: always return an exception with a more informative error message
2. PR return empty array if boolean index array is all False #1198: always silently return an empty array (as numpy does)

Which one do you prefer?

[jswhit]

@dopplershift @shoyer any thoughts on this?

[shoyer]

Returning the size zero array like NumPy feels like the right thing to do

[dopplershift]

I agree, my lean was towards mirroring NumPy behavior.

[jswhit]

thanks - that's my thought as well. I will merge PR #1198 next week if we have no dissenting opinions by then.