issue_comments: 412095066

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https://github.com/pydata/xarray/issues/2059#issuecomment-412095066 https://api.github.com/repos/pydata/xarray/issues/2059 412095066 MDEyOklzc3VlQ29tbWVudDQxMjA5NTA2Ng== 32801740 2018-08-10T14:14:12Z 2018-08-10T14:14:12Z CONTRIBUTOR

Currently, the dtype does not seem to roundtrip faithfully. When I write np.unicode_ / str to file, it gets transformed to object when I subsequently read it from disk. I am using xarray 0.10.8 with Python 3 on Windows.

This can be reproduced by inserting the following line in the script above (and adjusting the print statement accordingly)

python with xr.open_dataset(filename) as ds: read_dtype = ds['data'].dtype which gives:

Python version | NetCDF version | NumPy datatype | NetCDF datatype|Numpy datatype (read) -- | -- | -- | --|-- | Python 3 | NETCDF3 | np.string_ / bytes | NC_CHAR | \|S3 | | Python 3 | NETCDF4 | np.string_ / bytes | NC_CHAR | \|S3 | | Python 3 | NETCDF3 | np.unicode_ / str | NC_CHAR with UTF-8 encoding | object | | Python 3 | NETCDF4 | np.unicode_ / str | NC_STRING | object | | Python 3 | NETCDF3 | object bytes/bytes | NC_CHAR | \|S3 | | Python 3 | NETCDF4 | object bytes/bytes | NC_CHAR | \|S3 | | Python 3 | NETCDF3 | object unicode/str | NC_CHAR with UTF-8 encoding | object | | Python 3 | NETCDF4 | object unicode/str | NC_STRING | object |

Also object bytes/bytes seems not to roundtrip nicely as it seems to be converted to np.string_ / bytes.

Is it possible to preserve dtype when persisting xarray Datasets/DataArrays to disk?

 
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