ENH: refactor Concatenator to work for ndim > 2, add join-multiple to…

… Panel, #115

pandas/core/frame.py

@@ -299,6 +299,15 @@ def __init__(self, data=None, index=None, columns=None, dtype=None,
 
         NDFrame.__init__(self, mgr)
 
+    @classmethod
+    def _from_axes(cls, data, axes):
+        # for construction from BlockManager
+        if isinstance(data, BlockManager):
+            return cls(data)
+        else:
+            columns, index = axes
+            return cls(data, index=index, columns=columns, copy=False)
+
     def _init_mgr(self, mgr, index, columns, dtype=None, copy=False):
         if columns is not None:
             mgr = mgr.reindex_axis(columns, axis=0, copy=False)
@@ -2751,9 +2760,6 @@ def append(self, other, ignore_index=False, verify_integrity=True):
         return concat(to_concat, ignore_index=ignore_index,
                       verify_integrity=verify_integrity)
 
-    def _get_raw_column(self, col):
-        return self._data.get(col)
-
     def join(self, other, on=None, how='left', lsuffix='', rsuffix=''):
         """
         Join columns with other DataFrame either on index or on a key
@@ -2815,12 +2821,12 @@ def _join_compat(self, other, on=None, how='left', lsuffix='', rsuffix=''):
             # join indexes only using concat
             if how == 'left':
                 how = 'outer'
-                join_index = self.index
+                join_axes = [self.index]
             else:
-                join_index = None
+                join_axes = None
 
             return concat([self] + list(other), axis=1, join=how,
-                          join_index=join_index, verify_integrity=True)
+                          join_axes=join_axes, verify_integrity=True)
 
     def merge(self, right, how='inner', on=None, left_on=None, right_on=None,
               left_index=False, right_index=False, sort=True,

pandas/core/groupby.py

@@ -1144,7 +1144,7 @@ def transform(self, func, *args, **kwargs):
                 applied.append(res)
 
         concat_index = obj.columns if self.axis == 0 else obj.index
-        concatenated = concat(applied, join_index=concat_index,
+        concatenated = concat(applied, join_axes=[concat_index],
                               axis=self.axis, verify_integrity=False)
         return concatenated.reindex_like(obj)
 

pandas/core/panel.py

@@ -232,6 +232,16 @@ def __init__(self, data=None, items=None, major_axis=None, minor_axis=None,
 
         NDFrame.__init__(self, mgr, axes=axes, copy=copy, dtype=dtype)
 
+    @classmethod
+    def _from_axes(cls, data, axes):
+        # for construction from BlockManager
+        if isinstance(data, BlockManager):
+            return cls(data)
+        else:
+            items, major, minor = axes
+            return cls(data, items=items, major_axis=major,
+                       minor_axis=minor, copy=False)
+
     def _init_dict(self, data, axes, dtype=None):
         items, major, minor = axes
 
@@ -1067,13 +1077,13 @@ def truncate(self, before=None, after=None, axis='major'):
 
         return self.reindex(**{axis : new_index})
 
-    def join(self, other, how=None, lsuffix='', rsuffix=''):
+    def join(self, other, how='left', lsuffix='', rsuffix=''):
         """
         Join items with other Panel either on major and minor axes column
 
         Parameters
         ----------
-        other : Panel
+        other : Panel or list of Panels
             Index should be similar to one of the columns in this one
         how : {'left', 'right', 'outer', 'inner'}
             How to handle indexes of the two objects. Default: 'left'
@@ -1091,16 +1101,30 @@ def join(self, other, how=None, lsuffix='', rsuffix=''):
         -------
         joined : Panel
         """
-        if how is None:
-            how = 'left'
-        return self._join_index(other, how, lsuffix, rsuffix)
-
-    def _join_index(self, other, how, lsuffix, rsuffix):
-        join_major, join_minor = self._get_join_index(other, how)
-        this = self.reindex(major=join_major, minor=join_minor)
-        other = other.reindex(major=join_major, minor=join_minor)
-        merged_data = this._data.merge(other._data, lsuffix, rsuffix)
-        return self._constructor(merged_data)
+        from pandas.tools.merge import concat
+
+        if isinstance(other, Panel):
+            join_major, join_minor = self._get_join_index(other, how)
+            this = self.reindex(major=join_major, minor=join_minor)
+            other = other.reindex(major=join_major, minor=join_minor)
+            merged_data = this._data.merge(other._data, lsuffix, rsuffix)
+            return self._constructor(merged_data)
+        else:
+            if lsuffix or rsuffix:
+                raise ValueError('Suffixes not supported when passing multiple '
+                                 'panels')
+
+            if how == 'left':
+                how = 'outer'
+                join_axes = [self.major_axis, self.minor_axis]
+            elif how == 'right':
+                raise ValueError('Right join not supported with multiple '
+                                 'panels')
+            else:
+                join_axes = None
+
+            return concat([self] + list(other), axis=0, join=how,
+                          join_axes=join_axes, verify_integrity=True)
 
     def _get_join_index(self, other, how):
         if how == 'left':

pandas/sparse/frame.py

@@ -3,7 +3,7 @@
 float64 data
 """
 
-# pylint: disable=E1101,E1103,W0231
+# pylint: disable=E1101,E1103,W0231,E0202
 
 from numpy import nan
 import numpy as np
@@ -13,10 +13,24 @@
 from pandas.core.series import Series
 from pandas.core.frame import (DataFrame, extract_index, _prep_ndarray,
                                _default_index)
+from pandas.util.decorators import cache_readonly
 import pandas.core.datetools as datetools
 
 from pandas.sparse.series import SparseSeries
 
+
+class _SparseMockBlockManager(object):
+
+    def __init__(self, sp_frame):
+        self.sp_frame = sp_frame
+
+    def get(self, item):
+        return self.sp_frame[item].values
+
+    @property
+    def axes(self):
+        return [self.sp_frame.columns, self.sp_frame.index]
+
 class SparseDataFrame(DataFrame):
     """
     DataFrame containing sparse floating point data in the form of SparseSeries
@@ -71,6 +85,14 @@ def __init__(self, data=None, index=None, columns=None,
         self.columns = columns
         self.index = index
 
+    def _from_axes(self, data, axes):
+        columns, index = axes
+        return self._constructor(data, index=index, columns=columns)
+
+    @cache_readonly
+    def _data(self):
+        return _SparseMockBlockManager(self)
+
     def _get_numeric_columns(self):
         # everything is necessarily float64
         return self.columns
@@ -512,9 +534,6 @@ def _rename_columns_inplace(self, mapper):
         self.columns = new_columns
         self._series = new_series
 
-    def _get_raw_column(self, col):
-        return self._series[col].values
-
     def add_prefix(self, prefix):
         f = (('%s' % prefix) + '%s').__mod__
         return self.rename(columns=f)

pandas/tests/test_panel.py

@@ -902,48 +902,6 @@ def test_shift(self):
 
         self.assertRaises(Exception, self.panel.shift, 1, axis='items')
 
-    def test_join(self):
-        p1 = self.panel.ix[:2, :10, :3]
-        p2 = self.panel.ix[2:, 5:, 2:]
-
-        # left join
-        result = p1.join(p2)
-        expected = p1.copy()
-        expected['ItemC'] = p2['ItemC']
-        assert_panel_equal(result, expected)
-
-        # right join
-        result = p1.join(p2, how='right')
-        expected = p2.copy()
-        expected['ItemA'] = p1['ItemA']
-        expected['ItemB'] = p1['ItemB']
-        expected = expected.reindex(items=['ItemA', 'ItemB', 'ItemC'])
-        assert_panel_equal(result, expected)
-
-        # inner join
-        result = p1.join(p2, how='inner')
-        expected = self.panel.ix[:, 5:10, 2:3]
-        assert_panel_equal(result, expected)
-
-        # outer join
-        result = p1.join(p2, how='outer')
-        expected = p1.reindex(major=self.panel.major_axis,
-                              minor=self.panel.minor_axis)
-        expected = expected.join(p2.reindex(major=self.panel.major_axis,
-                                            minor=self.panel.minor_axis))
-        assert_panel_equal(result, expected)
-
-    def test_join_overlap(self):
-        p1 = self.panel.ix[['ItemA', 'ItemB', 'ItemC']]
-        p2 = self.panel.ix[['ItemB', 'ItemC']]
-
-        joined = p1.join(p2, lsuffix='_p1', rsuffix='_p2')
-        p1_suf = p1.ix[['ItemB', 'ItemC']].add_suffix('_p1')
-        p2_suf = p2.ix[['ItemB', 'ItemC']].add_suffix('_p2')
-        no_overlap = self.panel.ix[['ItemA']]
-        expected = p1_suf.join(p2_suf).join(no_overlap)
-        assert_panel_equal(joined, expected)
-
     def test_repr_empty(self):
         empty = Panel()
         repr(empty)