Moved repeated strings to constants & tidied up docstrings

Author: robintw

xarray/backends/api.py

@@ -15,6 +15,8 @@
 from ..core.utils import close_on_error, is_remote_uri
 from ..core.pycompat import basestring
 
+DATAARRAY_NAME = '__xarray_dataarray_name__'
+DATAARRAY_VARIABLE = '__xarray_dataarray_variable__'
 
 def _get_default_engine(path, allow_remote=False):
     if allow_remote and is_remote_uri(path):  # pragma: no cover
@@ -348,21 +350,21 @@ def open_dataarray(filename_or_obj, group=None, decode_cf=True,
                            chunks, lock, drop_variables)
 
     if len(dataset.data_vars) != 1:
-        raise ValueError('Given file dataset contains more than one variable. '
-                         'Please read with xarray.open_dataset and then select '
-                         'the variable you want.')
+        raise ValueError('Given file dataset contains more than one data '
+                         'variable. Please read with xarray.open_dataset and '
+                         'then select the variable you want.')
     else:
         data_array, = dataset.data_vars.values()
 
     data_array._file_obj = dataset._file_obj
 
     # Reset names if they were changed during saving
     # to ensure that we can 'roundtrip' perfectly
-    if '__xarray_dataarray_name__' in dataset.attrs:
-        data_array.name = dataset.attrs['__xarray_dataarray_name__']
-        del dataset.attrs['__xarray_dataarray_name__']
+    if DATAARRAY_NAME in dataset.attrs:
+        data_array.name = dataset.attrs[DATAARRAY_NAME]
+        del dataset.attrs[DATAARRAY_NAME]
 
-    if data_array.name == '__xarray_dataarray_variable__':
+    if data_array.name == DATAARRAY_VARIABLE:
         data_array.name = None
 
     return data_array

xarray/core/common.py

@@ -579,7 +579,7 @@ def where(self, cond, other=None, drop=False):
         return outobj._where(outcond)
 
     def close(self):
-        """Close any files linked to this dataset
+        """Close any files linked to this object
         """
         if self._file_obj is not None:
             self._file_obj.close()

xarray/core/dataarray.py

@@ -1152,14 +1152,16 @@ def to_netcdf(self, *args, **kwargs):
 
         All parameters are passed directly to `xarray.Dataset.to_netcdf`.
         """
+        from ..backends.api import DATAARRAY_NAME, DATAARRAY_VARIABLE
+
         if not self.name:
             # If no name is set then use a generic xarray name
-            dataset = self.to_dataset(name='__xarray_dataarray_variable__')
+            dataset = self.to_dataset(name=DATAARRAY_VARIABLE)
         elif self.name in list(self.coords):
             # The name is the same as one of the coords names, which netCDF
             # doesn't support, so rename it but keep track of the old name
-            dataset = self.to_dataset(name='__xarray_dataarray_variable__')
-            dataset.attrs['__xarray_dataarray_name__'] = self.name
+            dataset = self.to_dataset(name=DATAARRAY_VARIABLE)
+            dataset.attrs[DATAARRAY_NAME] = self.name
         else:
             # No problems with the name - so we're fine!
             dataset = self.to_dataset()