# cf.Coordinate.fill_value

`Coordinate.``fill_value`(default=None)

  Return the data array missing data value.

  This is the value of the `missing_value` CF property, or if that is not set, the value of the `_FillValue` CF property, else if that is not set, `None`. In the last case the default `numpy` missing data value for the array’s data type is assumed if a missing data value is required.

    Parameters: | default: optional If the missing value is unset then return this value. By default, default is `None`. If default is the special value `'netCDF'` then return the netCDF default value appropriate to the data array’s data type is used. These may be found as follows:
        >>> import netCDF4
        >>> print netCDF4.default_fillvals
  Returns: | out: The missing data value, or the value specified by default if one has not been set.
  Examples: |

      >>> f.fill_value()
      None
      >>> f._FillValue = -1e30
      >>> f.fill_value()
      -1e30
      >>> f.missing_value = 1073741824
      >>> f.fill_value()
      1073741824
      >>> del f.missing_value
      >>> f.fill_value()
      -1e30
      >>> del f._FillValue
      >>> f.fill_value()
      None
      >>> f,dtype
      dtype('float64')
      >>> f.fill_value(default='netCDF')
      9.969209968386869e+36
      >>> f._FillValue = -999
      >>> f.fill_value(default='netCDF')
      -999