REF: reuse general code for Index appending

Author: toobaz

pandas/core/indexes/base.py

@@ -1680,23 +1680,27 @@ def append(self, other):
         names = set([obj.name for obj in to_concat])
         name = None if len(names) > 1 else self.name
 
-        if self.is_categorical():
-            # if calling index is category, don't check dtype of others
-            from pandas.core.indexes.category import CategoricalIndex
-            return CategoricalIndex._append_same_dtype(self, to_concat, name)
+        res = self._concat(to_concat)
 
-        typs = _concat.get_dtype_kinds(to_concat)
+        res.name = name
+        return res
 
+    def _concat(self, to_concat):
+        """
+        Concatenate to_concat to single Index
+        """
+        typs = _concat.get_dtype_kinds(to_concat)
         if len(typs) == 1:
-            return self._append_same_dtype(to_concat, name=name)
-        return _concat._concat_index_asobject(to_concat, name=name)
+            return self._concat_same_dtype(to_concat)
+        else:
+            return _concat._concat_index_asobject(to_concat)
 
-    def _append_same_dtype(self, to_concat, name):
+    def _concat_same_dtype(self, to_concat):
         """
-        Concatenate to_concat which has the same class
+        Concatenate to_concat which has the same dtype
         """
         # must be overrided in specific classes
-        return _concat._concat_index_asobject(to_concat, name)
+        return _concat._concat_index_asobject(to_concat)
 
     _index_shared_docs['take'] = """
         return a new %(klass)s of the values selected by the indices

pandas/core/indexes/category.py

@@ -546,6 +546,13 @@ def _convert_arr_indexer(self, keyarr):
     def _convert_index_indexer(self, keyarr):
         return self._shallow_copy(keyarr)
 
+    def _concat(self, to_concat):
+        """
+        Concatenate to_concat to single Index
+        """
+        # if calling index is category, don't check dtype of others
+        return self._concat_same_dtype(to_concat)
+
     @Appender(_index_shared_docs['take'] % _index_doc_kwargs)
     def take(self, indices, axis=0, allow_fill=True,
              fill_value=None, **kwargs):
@@ -615,17 +622,14 @@ def insert(self, loc, item):
         codes = np.concatenate((codes[:loc], code, codes[loc:]))
         return self._create_from_codes(codes)
 
-    def _append_same_dtype(self, to_concat, name):
+    def _concat_same_dtype(self, to_concat):
         """
         Concatenate to_concat which has the same class
         ValueError if other is not in the categories
         """
         to_concat = [self._is_dtype_compat(c) for c in to_concat]
         codes = np.concatenate([c.codes for c in to_concat])
-        result = self._create_from_codes(codes, name=name)
-        # if name is None, _create_from_codes sets self.name
-        result.name = name
-        return result
+        return self._create_from_codes(codes)
 
     def _codes_for_groupby(self, sort):
         """ Return a Categorical adjusted for groupby """

pandas/core/indexes/range.py

@@ -443,33 +443,14 @@ def join(self, other, how='left', level=None, return_indexers=False,
         return super(RangeIndex, self).join(other, how, level, return_indexers,
                                             sort)
 
-    def append(self, other):
-        """
-        Append a collection of Index options together
-
-        Parameters
-        ----------
-        other : Index or list/tuple of indices
-
-        Returns
-        -------
-        appended : RangeIndex if all indexes are consecutive RangeIndexes,
-                   otherwise Int64Index or Index
-        """
-
-        to_concat = [self]
-
-        if isinstance(other, (list, tuple)):
-            to_concat = to_concat + list(other)
-        else:
-            to_concat.append(other)
+    def _concat_same_dtype(self, indexes):
 
-        if not all([isinstance(i, RangeIndex) for i in to_concat]):
-            return super(RangeIndex, self).append(other)
+        if not all([isinstance(i, RangeIndex) for i in indexes]):
+            return super(RangeIndex, self)._concat_same_dtype(indexes)
 
         start = step = next = None
 
-        for obj in to_concat:
+        for obj in indexes:
             if not len(obj):
                 continue
 
@@ -481,13 +462,13 @@ def append(self, other):
             elif step is None:
                 # First non-empty index had only one element
                 if obj._start == start:
-                    return super(RangeIndex, self).append(other)
+                    return super(RangeIndex, self)._concat_same_dtype(indexes)
                 step = obj._start - start
 
             non_consecutive = ((step != obj._step and len(obj) > 1) or
                                (next is not None and obj._start != next))
             if non_consecutive:
-                return super(RangeIndex, self).append(other)
+                return super(RangeIndex, self)._concat_same_dtype(indexes)
 
             if step is not None:
                 next = obj[-1] + step
@@ -496,9 +477,7 @@ def append(self, other):
             start = obj._start
             step = obj._step
         stop = obj._stop if next is None else next
-        names = set([obj.name for obj in to_concat])
-        name = None if len(names) > 1 else self.name
-        return RangeIndex(start, stop, step, name=name)
+        return RangeIndex(start, stop, step)
 
     def __len__(self):
         """