DataFrame to dict with index orientation.

doc/source/whatsnew/v0.17.0.txt

@@ -174,6 +174,8 @@ Other enhancements
 
 - ``msgpack`` submodule has been updated to 0.4.6 with backward compatibility (:issue:`10581`)
 
+- ``DataFrame.to_dict`` now accepts the *index* option in ``orient`` keyword argument (:issue:`10844`).
+
 .. ipython :: python
 
    s = pd.Series(['A', 'B', 'C', 'A', 'B', 'D'])

pandas/core/frame.py

@@ -748,7 +748,7 @@ def to_dict(self, orient='dict'):
 
         Parameters
         ----------
-        orient : str {'dict', 'list', 'series', 'split', 'records'}
+        orient : str {'dict', 'list', 'series', 'split', 'records', 'index'}
             Determines the type of the values of the dictionary.
 
             - dict (default) : dict like {column -> {index -> value}}
@@ -758,6 +758,9 @@ def to_dict(self, orient='dict'):
               {index -> [index], columns -> [columns], data -> [values]}
             - records : list like
               [{column -> value}, ... , {column -> value}]
+            - index : dict like {index -> {column -> value}}
+
+            .. versionadded:: 0.17.0
 
             Abbreviations are allowed. `s` indicates `series` and `sp`
             indicates `split`.
@@ -782,6 +785,8 @@ def to_dict(self, orient='dict'):
         elif orient.lower().startswith('r'):
             return [dict((k, v) for k, v in zip(self.columns, row))
                     for row in self.values]
+        elif orient.lower().startswith('i'):
+            return dict((k, v.to_dict()) for k, v in self.iterrows())
         else:
             raise ValueError("orient '%s' not understood" % orient)
 

pandas/tests/test_frame.py

@@ -4474,9 +4474,16 @@ def test_to_dict(self):
 
         tm.assert_almost_equal(recons_data, expected_records)
 
+        # GH10844
+        recons_data = DataFrame(test_data).to_dict("i")
+
+        for k, v in compat.iteritems(test_data):
+            for k2, v2 in compat.iteritems(v):
+                self.assertEqual(v2, recons_data[k2][k])
+
     def test_to_dict_invalid_orient(self):
         df = DataFrame({'A':[0, 1]})
-        self.assertRaises(ValueError, df.to_dict, orient='invalid')
+        self.assertRaises(ValueError, df.to_dict, orient='xinvalid')
 
     def test_to_records_dt64(self):
         df = DataFrame([["one", "two", "three"],