Crop suffix of some dimension using SpatialCrop

[function2-llx]

Hello everyone. For some purpose I'd like to use the last 16 slices of my each MRI scan. For a numpy array x this can be done with x[0:None, 0:None, -16:None]. However currently I'm not able to find a way to achieve this with MONAI's SpatialCrop. In this case I need to pass roi_start=(0, 0, -16) and roi_end=(None, None, None) to construct SpatialCrop, but this leads to an exception raised here saying that:

TypeError: int() argument must be a string, a bytes-like object or a number, not 'NoneType'

While simple workaround by slicing it outside, or even using the transform of Lambda, is obvious, but it will be pretty cool if I could process my images only with transforms provided by MONAI, right?

Any suggestion will be appreciated!

[function2-llx]

Seems duplicate of #1929, I misunderstood that question at first.

Sorry about that, please refer to that discussion.

[rijobro]

Hi, suggested PR here. If you wanted to leave the last 16 in the z-direction and not touch anything else, this would be done with:

SpatialCrop(roi_slices=[slice(None), slice(None), slice(-16, None)])