issues: 522238536

This data as json

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
522238536 MDU6SXNzdWU1MjIyMzg1MzY= 3518 Have "unstack" return a boolean mask? 1200058 closed 0     1 2019-11-13T13:54:49Z 2019-11-16T14:36:43Z 2019-11-16T14:36:43Z NONE      

MCVE Code Sample

python arr = xr.DataArray(np.arange(6).reshape(2, 3), coords=[('x', ['a', 'b']), ('y', [0, 1, 2])]) arr stacked = arr.stack(z=('x', 'y')) stacked[:4].unstack().dtype

Expected Output

```python

arr = xr.DataArray(np.arange(6).reshape(2, 3), ... coords=[('x', ['a', 'b']), ('y', [0, 1, 2])]) arr <xarray.DataArray (x: 2, y: 3)> array([[0, 1, 2], [3, 4, 5]]) Coordinates: * x (x) <U1 'a' 'b' * y (y) int64 0 1 2 stacked = arr.stack(z=('x', 'y')) stacked[:4].unstack().dtype dtype('float64') ```

Problem Description

Unstacking changes the data type to float for NaN's. Are there thoughts on alternative options, e.g. fill_value=0 or return_boolean_mask, in order to retain the original data type?

Currently, I obtain a boolean missing array by checking for isnan. Then I call fillnan(0) and convert the data type back to integer. However, this is quite inefficient.

Output of xr.show_versions()

INSTALLED VERSIONS ------------------ commit: None python: 3.7.4 (default, Aug 13 2019, 20:35:49) [GCC 7.3.0] python-bits: 64 OS: Linux OS-release: 3.10.0-957.10.1.el7.x86_64 machine: x86_64 processor: x86_64 byteorder: little LC_ALL: None LANG: en_US.UTF-8 LOCALE: en_US.UTF-8 libhdf5: 1.10.4 libnetcdf: 4.6.1 xarray: 0.14.0 pandas: 0.25.1 numpy: 1.17.2 scipy: 1.3.1 netCDF4: 1.4.2 pydap: None h5netcdf: 0.7.4 h5py: 2.9.0 Nio: None zarr: 2.3.2 cftime: 1.0.3.4 nc_time_axis: None PseudoNetCDF: None rasterio: None cfgrib: None iris: None bottleneck: None dask: 2.5.2 distributed: 2.5.2 matplotlib: 3.1.1 cartopy: None seaborn: 0.9.0 numbagg: None setuptools: 41.4.0 pip: 19.2.3 conda: None pytest: 5.0.1 IPython: 7.8.0 sphinx: None 
{
    "url": "https://api.github.com/repos/pydata/xarray/issues/3518/reactions",
    "total_count": 0,
    "+1": 0,
    "-1": 0,
    "laugh": 0,
    "hooray": 0,
    "confused": 0,
    "heart": 0,
    "rocket": 0,
    "eyes": 0
}
   completed 13221727 issue

Links from other tables