html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/issues/448#issuecomment-116412391,https://api.github.com/repos/pydata/xarray/issues/448,116412391,MDEyOklzc3VlQ29tbWVudDExNjQxMjM5MQ==,1217238,2015-06-29T03:26:39Z,2015-06-29T03:26:39Z,MEMBER,"Xray doesn't use numpy ndarray subclasses, mostly because that would tie our underlying array implementations to numpy and stop us from using interesting alternative array implementations like [dask](http://dask.pydata.org/en/latest/array.html). Hence, `np.asanyarray` does not work either.
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,91676831
https://github.com/pydata/xarray/issues/448#issuecomment-116406425,https://api.github.com/repos/pydata/xarray/issues/448,116406425,MDEyOklzc3VlQ29tbWVudDExNjQwNjQyNQ==,1217238,2015-06-29T03:13:33Z,2015-06-29T03:13:33Z,MEMBER,"Unfortunately, there's no way to make `np.asarray` return anything other than a numpy array without metadata -- that's kind of the entire point of `asarray`.

We do have some other options, though. The first two already work:
- use `xray.Dataset.apply` to call a function, e.g., `ds.apply(db2w)`
- write a numpy universal function using numba:
  
  ``` python
  @numba.vectorize
  def db2w(arr):
      return 10 ** (arr / 20.0)
  ```
- we could write a modified version of `asarray` that passes through xray objects
- we could write a decorator that transforms a function to preserve/restore xray metadata, e.g.,
  
  ``` python
  def keep_metadata(func):
      def wrapper(array, **kwargs):
          return array.__array_wrap__(func(array))
      return wrapper
  
  @keep_metadata
  def db2w(arr):
      return 10 ** (np.asarray(arr) / 20.0)
  ```
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,91676831