issues: 454677926

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454677926 MDU6SXNzdWU0NTQ2Nzc5MjY= 3015 Assigning values to a subset of a dataset 23265127 closed 0     2 2019-06-11T13:03:16Z 2021-05-25T08:12:52Z 2021-05-25T08:12:52Z NONE      

Hi, can somebody tell me what is the "correct" way to manipulate a subset of the data contained in a Dataset?

Consider the following example: ``` import numpy as np import xarray as xr

shape = (3, 2) da1 = xr.DataArray(np.zeros(shape), dims=('x', 'y'), coords=dict(x=[1, 2, 3], y=[4, 5]), name='var1') da2 = xr.DataArray(np.zeros(shape), dims=('x', 'y'), coords=dict(x=[1, 2, 3], y=[4, 5]), name='var2') ```

I can easily change the value of variable 1 at a given coordinate in the first DataArray using the following syntax: da1.loc[dict(x=1, y=4)] = 1

However, if I merge both DataArrays into a single Dataset and want to change both variables at the same time, there seems to be no straightforward solution: ds = xr.merge([da1, da2]) ds.loc[dict(x=1, y=4)] = ... <-- what to write here?

The only solution I could come up with is to modify the two values separately, but this is neither very elegant nor scales with the number of variables: ds['var1'].loc[dict(x=1, y=4)] = 2 ds['var2'].loc[dict(x=1, y=4)] = 3

All I could find in the docs about this issue is:

Using indexing to assign values to a subset of dataset (e.g., ds[dict(space=0)] = 1) is not yet supported.

If not by indexing, what other (more compact) way exists? A potential solution might be to create a separate Dataset and then use the update method, but this seems overly complicated, too.

 
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