issue_comments

Sorry for my long time to reply, christmas... @keewis thank you a lot for your anwer, I am glad to hear subclass might be supported one day. At the end, those are the python tools the programmers we work with.

For the moment, I will try to implement Extending xarray as you pointed using "xr.register_dataset_accessor". Create a new class that cannot be identified as 'isinstance(object, xarray.Dataset)' might be an issue in my case.

Though we don't support it officially, I've found subclassing a Dataset can be useful when adding methods. Most operations on the object will not persist the subclass, though.

I assume this answered your question. If you disagree, feel free to reopen.

inheriting from a Dataset or DataArray is not something we support right now, although that might change in the future.

The reason your examples fail with a RecursionError is a different one, though, you also get the same error if you remove all references to xarray and pass a string to your class. As pointed out in the SO question you referenced, you need to change your __init__: ```python class MyClass: slots = ("dataset",)

def __init__(self, ds):
    self.__class__.dataset.__set__(self, ds)

def __getattr__(self, k):
    return getattr(self.dataset, k)

def __setattr__(self, k, v):
    setattr(self.dataset, k, v)

ds = xr.Dataset() x = MyClass(ds) `` but I've also seen the use ofnewinstead ofinit` to avoid this somewhat ugly trick.

Be aware that the result of __getattr__ as it is right now will remove the custom class, so if you would like to avoid that you will have to add some sort of check: python def __getattr__(self, k): result = getattr(self.dataset, k) if isinstance(result, (xr.Dataset, xr.DataArray)): return type(self)(result) else: return result