issue_comments: 333175863

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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/1598#issuecomment-333175863	https://api.github.com/repos/pydata/xarray/issues/1598	333175863	MDEyOklzc3VlQ29tbWVudDMzMzE3NTg2Mw==	13837821	2017-09-29T16:37:07Z	2017-09-29T16:37:20Z	CONTRIBUTOR	@jhamman In brief, it's weird. Engine \| encoding['_FillValue'] = False \| Do nothing ----- \| ----- \| ----- netCDF4 \| Filling off \| Filling on scipy \| Filling off \| Filling off h5netcdf \| Filling on \| Filling off So, this is some peculiar behavior. Setting `_FillValue` to `False` works for netCDF4 (as we have seen), has no effect using the scipy engine, and seems to do the opposite of intended for h5netcdf. Code below: ``` import xarray as xr import numpy as np import pandas as pd ds = xr.Dataset({'foo': (('x', 'y'), np.random.rand(4, 5))}, coords={'x': [10, 20, 30, 40], 'y': pd.date_range('2000-01-01', periods=5), 'z': ('x', list('abcd'))}) ds.to_netcdf('notset_scipy.nc', engine='scipy') ds.to_netcdf('notset_netcdf4.nc', engine='netcdf4') ds.to_netcdf('notset_h5netcdf.nc', engine='h5netcdf') ds.y.encoding['_FillValue'] = False ds.to_netcdf('False_scipy.nc', engine='scipy') ds.to_netcdf('False_netcdf4.nc', engine='netcdf4') ds.to_netcdf('False_h5netcdf.nc', engine='h5netcdf') ``` netCDF4 `$ ncinfo -v y notset_netcdf4.nc <type 'netCDF4._netCDF4.Variable'> int64 y(y) units: days since 2000-01-01 00:00:00 calendar: proleptic_gregorian unlimited dimensions: current shape = (5,) filling on, default _FillValue of -9223372036854775806 used` `$ ncinfo -v y False_netcdf4.nc <type 'netCDF4._netCDF4.Variable'> int64 y(y) units: days since 2000-01-01 00:00:00 calendar: proleptic_gregorian unlimited dimensions: current shape = (5,) filling off` scipy `$ ncinfo -v y notset_scipy.nc <type 'netCDF4._netCDF4.Variable'> int32 y(y) units: days since 2000-01-01 00:00:00 calendar: proleptic_gregorian unlimited dimensions: current shape = (5,) filling off` `$ ncinfo -v y False_scipy.nc <type 'netCDF4._netCDF4.Variable'> int32 y(y) units: days since 2000-01-01 00:00:00 calendar: proleptic_gregorian _FillValue: 0 unlimited dimensions: current shape = (5,) filling off` h5netcdf `$ ncinfo -v y notset_h5netcdf.nc <type 'netCDF4._netCDF4.Variable'> int64 y(y) units: days since 2000-01-01 00:00:00 calendar: proleptic_gregorian unlimited dimensions: current shape = (5,) filling off` `$ ncinfo -v y False_h5netcdf.nc <type 'netCDF4._netCDF4.Variable'> int64 y(y) _FillValue: 0 units: days since 2000-01-01 00:00:00 calendar: proleptic_gregorian unlimited dimensions: current shape = (5,) filling on`	{ "total_count": 0, "+1": 0, "-1": 0, "laugh": 0, "hooray": 0, "confused": 0, "heart": 0, "rocket": 0, "eyes": 0 }		261403591