issues: 324758225

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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
324758225 MDU6SXNzdWUzMjQ3NTgyMjU= 2165 CFTimeIndex improperly handles string slice for length-1 indexes 6628425 closed 0     0 2018-05-21T00:51:55Z 2018-05-21T08:02:35Z 2018-05-21T08:02:35Z MEMBER      

Code Sample, a copy-pastable example if possible

``` In [1]: import xarray as xr

In [2]: import cftime

In [3]: index = xr.CFTimeIndex([cftime.DatetimeNoLeap(1, 1, 1)])

In [4]: da = xr.DataArray([1], coords=[index], dims=['time'])

In [5]: da.sel(time=slice('0001', '0001')) Out[5]: <xarray.DataArray (time: 0)> array([], dtype=int64) Coordinates: * time (time) object ```

Problem description

When a CFTimeIndex is created with a single element, slicing using strings does not work; the example above should behave analogously to as it does when using a DatetimeIndex: ``` In [9]: import pandas as pd

In [10]: index = pd.DatetimeIndex(['2000-01-01'])

In [11]: da = xr.DataArray([1], coords=[index], dims=['time'])

In [12]: da.sel(time=slice('2000', '2000')) Out[12]: <xarray.DataArray (time: 1)> array([1]) Coordinates: * time (time) datetime64[ns] 2000-01-01 ``` I have a fix for this, which I will push shortly.

Expected Output

In [5]: da.sel(time=slice('0001', '0001')) Out[5]: <xarray.DataArray (time: 1)> array([1]) Coordinates: * time (time) object 0001-01-01 00:00:00

Output of xr.show_versions()

INSTALLED VERSIONS ------------------ commit: None python: 3.6.1.final.0 python-bits: 64 OS: Darwin OS-release: 17.4.0 machine: x86_64 processor: i386 byteorder: little LC_ALL: None LANG: en_US.UTF-8 LOCALE: en_US.UTF-8 xarray: 0.10.4 pandas: 0.20.2 numpy: 1.13.1 scipy: 0.19.1 netCDF4: 1.4.0 h5netcdf: 0.5.1 h5py: 2.8.0 Nio: None zarr: None bottleneck: 1.2.0 cyordereddict: None dask: 0.15.0 distributed: 1.17.1 matplotlib: 2.0.2 cartopy: None seaborn: None setuptools: 33.1.1.post20170320 pip: 9.0.1 conda: None pytest: 3.1.2 IPython: 6.1.0 sphinx: None 
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