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/3945#issuecomment-1115469330,https://api.github.com/repos/pydata/xarray/issues/3945,1115469330,IC_kwDOAMm_X85CfLYS,26384082,2022-05-02T23:37:47Z,2022-05-02T23:37:47Z,NONE,"In order to maintain a list of currently relevant issues, we mark issues as stale after a period of inactivity

If this issue remains relevant, please comment here or remove the `stale` label; otherwise it will be marked as closed automatically
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,595784008
https://github.com/pydata/xarray/issues/3945#issuecomment-610426980,https://api.github.com/repos/pydata/xarray/issues/3945,610426980,MDEyOklzc3VlQ29tbWVudDYxMDQyNjk4MA==,2448579,2020-04-07T14:41:08Z,2020-04-07T14:41:08Z,MEMBER,xhistogram probably does what you want: https://github.com/xgcm/xhistogram,"{""total_count"": 1, ""+1"": 1, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,595784008
https://github.com/pydata/xarray/issues/3945#issuecomment-610407293,https://api.github.com/repos/pydata/xarray/issues/3945,610407293,MDEyOklzc3VlQ29tbWVudDYxMDQwNzI5Mw==,1200058,2020-04-07T14:06:03Z,2020-04-07T14:17:12Z,NONE,"First prototype:
```python
def value_counts(v, global_unique_values, newdim: str):
    unique_values, counts = dask.compute(*np.unique(v, return_counts=True))
    
    # find out where in `global_unique_values` the unique values of `v` are located
    _, idx1, idx2 = np.intersect1d(unique_values, global_unique_values, return_indices=True)
    
    # assign values according to `global_unique_values`
    retval = np.zeros_like(global_unique_values)
    retval[idx2] = counts[idx1]
    
    # ## alternative:
    # counts = xr.DataArray(
    #     counts, 
    #     dims=[newdim, ],
    #     coords={newdim: unique_values},
    # )
    # counts, = xr.align(counts, indexes={newdim: global_unique_values}, fill_value=0)
    
    return retval

def xr_value_counts(obj, unique_values=None, **kwargs):
    (newdim, apply_dims), = kwargs.items()
    
    if type(apply_dims) == str:
        # convert scalars to list
        apply_dims = [apply_dims]
    if type(apply_dims) != list:
        # cast iterables to list
        apply_dims = [*apply_dims]
    
    if not unique_values:
        # map(np.unique) and reduce(np.unique)
        unique_values = np.unique(da.map_blocks(np.unique, obj.data.flatten()).compute())
    else:
        unique_values = np.sort(unique_values)
    
    retval = xr.apply_ufunc(
        lambda v: value_counts(v, global_unique_values=unique_values, newdim=newdim),
        obj,
        input_core_dims=[apply_dims],
        output_core_dims=[[newdim]],
        dask=""allowed"",
        vectorize=True,
    )
    retval.coords[newdim] = unique_values
    
    return retval

test_da = xr.DataArray(
    [
        [0,1,1,1,3,4], 
        [0,6,1,1,3,4],
    ],
    dims=[""dim_0"", ""dim_1""],
    coords={""dim_1"": [2,5,7,4,3,6]},
)

test_values = xr_value_counts(test_da, value_counts=""dim_1"")

assert np.all(
    test_values.values == np.array([
        [1, 3, 1, 1, 0],
        [1, 2, 1, 1, 1]
    ])
)

assert np.all(
    test_values.value_counts == np.array([0, 1, 3, 4, 6])
)
```

Example:
```python
test_da = xr.DataArray(
    [
        [0,1,1,1,3,4], 
        [0,6,1,1,3,4],
    ],
    dims=[""dim_0"", ""dim_1""],
    coords={""dim_1"": [2,5,7,4,3,6]},
)

print(test_da)
# <xarray.DataArray (dim_0: 2, dim_1: 6)>
# array([[0, 1, 1, 1, 3, 4],
#        [0, 6, 1, 1, 3, 4]])
# Coordinates:
#   * dim_1    (dim_1) int64 2 5 7 4 3 6
# Dimensions without coordinates: dim_0

print(xr_value_counts(test_da, value_counts=""dim_1""))
# <xarray.DataArray (dim_0: 2, value_counts: 5)>
# array([[1, 3, 1, 1, 0],
#        [1, 2, 1, 1, 1]])
# Coordinates:
#   * value_counts  (value_counts) int64 0 1 3 4 6
# Dimensions without coordinates: dim_0
```

Probably not the fastest solution and executes eagerly but it works.
What do you think?","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,595784008