issues: 753852119

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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
753852119 MDU6SXNzdWU3NTM4NTIxMTk= 4628 Lazy concatenation of arrays 1386642 open 0     5 2020-11-30T22:32:08Z 2022-05-10T17:02:34Z   CONTRIBUTOR      

Is your feature request related to a problem? Please describe. Concatenating xarray objects forces the data to load. I recently learned about this object allowing lazy indexing into an DataArrays/sets without using dask. Concatenation along a single dimension is the inverse operation of slicing, so it seems natural to also support it. Also, concatenating along dimensions (e.g. "run"/"simulation"/"ensemble") can be a common merging workflow.

Describe the solution you'd like

xr.concat([a, b], dim=...) does not load any data in a or b.

Describe alternatives you've considered One could rename the variables in a and b to allow them to be merged (e.g. a['air_temperature'] -> "air_temperature_a"), but it's more natural to make a new dimension.

Additional context

This is useful when not using dask for performance reasons (e.g. using another parallelism engine like Apache Beam).

 
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