issues: 609108666

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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
609108666 MDU6SXNzdWU2MDkxMDg2NjY= 4016 Concatenate DataArrays on one dim when another dim has difference sizes 30388627 closed 0     8 2020-04-29T14:36:10Z 2020-05-06T00:54:39Z 2020-04-30T12:12:11Z NONE      

It's impossible to concatenate two arrays on same named dimensions with different sizes.

MCVE Code Sample

```python import xarray as xr import pandas as pd

a = xr.DataArray([0], dims=['x']) b = xr.DataArray([1, 2, 3], dims=['x']) a = a.expand_dims("time") b = b.expand_dims("time") a.coords["time"] = pd.DatetimeIndex(['2020-02-14 05:25:10']) b.coords["time"] = pd.DatetimeIndex(['2020-02-14 05:25:10']) c = xr.concat([a, b], dim='time') print(c) ```

Expected Output

[[0], [1, 2, 3]]

Problem Description

File "C:\Users\Xin\Desktop\test_github.py", line 10, in <module> c = xr.concat([a, b], dim='time') File "E:\miniconda3\envs\satpy\lib\site-packages\xarray\core\concat.py", line 135, in concat return f(objs, dim, data_vars, coords, compat, positions, fill_value, join) File "E:\miniconda3\envs\satpy\lib\site-packages\xarray\core\concat.py", line 455, in _dataarray_concat join=join, File "E:\miniconda3\envs\satpy\lib\site-packages\xarray\core\concat.py", line 319, in _dataset_concat *datasets, join=join, copy=False, exclude=[dim], fill_value=fill_value File "E:\miniconda3\envs\satpy\lib\site-packages\xarray\core\alignment.py", line 327, in align % (dim, sizes) ValueError: arguments without labels along dimension 'x' cannot be aligned because they have different dimension sizes: {1, 3}

Versions

Output of <tt>xr.show_versions()</tt> INSTALLED VERSIONS ------------------ commit: None python: 3.7.6 | packaged by conda-forge | (default, Jan 7 2020, 21:48:41) [MSC v.1916 64 bit (AMD64)] python-bits: 64 OS: Windows OS-release: 10 machine: AMD64 processor: Intel64 Family 6 Model 158 Stepping 9, GenuineIntel byteorder: little LC_ALL: None LANG: None LOCALE: None.None libhdf5: 1.10.5 libnetcdf: 4.7.3 xarray: 0.15.1 pandas: 1.0.3 numpy: 1.18.1 scipy: 1.4.1 netCDF4: 1.5.3 pydap: None h5netcdf: None h5py: 2.10.0 Nio: None zarr: 2.4.0 cftime: 1.1.1.2 nc_time_axis: None PseudoNetCDF: None rasterio: 1.1.3 cfgrib: None iris: None bottleneck: None dask: 2.10.1 distributed: 2.14.0 matplotlib: 3.2.1 cartopy: 0.17.0 seaborn: 0.10.0 numbagg: None setuptools: 46.1.3.post20200325 pip: 20.0.2 conda: None pytest: None IPython: 7.13.0 sphinx: 2.4.4 
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   completed 13221727 issue

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