issues: 1379000408

This data as json

id node_id number title user state locked assignee milestone comments created_at updated_at closed_at author_association active_lock_reason draft pull_request body reactions performed_via_github_app state_reason repo type
1379000408 I_kwDOAMm_X85SMeBY 7057 Hook for better control over copy behavior with duck-arrays? 12912489 open 0     0 2022-09-20T08:11:12Z 2022-09-20T08:12:22Z   NONE      

Context

By using copy(deep=False) custom operations may avoid copying large amounts of data but can modify, e.g., coord dicts:

```python tmp = da.copy(deep=False) del tmp.coords['abc']

Use tmp

`` Whenda` wraps a duck-array with substructure the current implementation is insufficient:

```python tmp = da.copy(deep=False)

Imagine a duck-array similar to numpy.ma but with a dict of masks

del tmp.data.masks['abc'] # Bad: breaks da

Use tmp

```

Describe the solution you'd like

Currently there does not appear a solution to this, unless we know details about the duck array. Therefore, I wonder if we need an additional "hook" that duck-arrays may provide, which could be called by Xarray to make a non-deep copy?

python class MyDuckArray: def _copy_shallow_(self): # TODO: better name """Copy everything except buffers"""

```python

in xarray.Variable

def copy(self, deep=True): if deep: data = copy.deepcopy(data) elif hasattr(data, 'copy_shallow'): data = data.copy_shallow() ```

Additional context

This is the current implementation for Variable. There is no operation for deep=False: https://github.com/pydata/xarray/blob/716973e41060184beebd64935afe196a805ef481/xarray/core/variable.py#L956-L957

 
{
    "url": "https://api.github.com/repos/pydata/xarray/issues/7057/reactions",
    "total_count": 0,
    "+1": 0,
    "-1": 0,
    "laugh": 0,
    "hooray": 0,
    "confused": 0,
    "heart": 0,
    "rocket": 0,
    "eyes": 0
}
     13221727 issue

Links from other tables