Merge pull request #3558 from cpcloud/panel-transpose-args-fix-3556

fix panel tranpose arguments api bug

Author: jreback

RELEASE.rst

@@ -102,6 +102,7 @@ pandas 0.11.1
     e.g. add datetimes, multiple timedelta x datetime
   - Fix ``.diff`` on datelike and timedelta operations (GH3100_)
   - ``combine_first`` not returning the same dtype in cases where it can (GH3552_)
+  - Fixed bug with ``Panel.transpose`` argument aliases (GH3556_)
 
 .. _GH3164: https://github.com/pydata/pandas/issues/3164
 .. _GH2786: https://github.com/pydata/pandas/issues/2786
@@ -140,6 +141,7 @@ pandas 0.11.1
 .. _GH3552: https://github.com/pydata/pandas/issues/3552
 .. _GH3562: https://github.com/pydata/pandas/issues/3562
 .. _GH3493: https://github.com/pydata/pandas/issues/3493
+.. _GH3556: https://github.com/pydata/pandas/issues/3556
 
 
 pandas 0.11.0

pandas/core/panel.py

@@ -1166,16 +1166,35 @@ def transpose(self, *args, **kwargs):
         -------
         y : Panel (new object)
         """
-
         # construct the args
         args = list(args)
+        aliases = tuple(kwargs.iterkeys())
+
         for a in self._AXIS_ORDERS:
             if not a in kwargs:
-                try:
-                    kwargs[a] = args.pop(0)
-                except (IndexError):
-                    raise ValueError(
-                        "not enough arguments specified to transpose!")
+                where = map(a.startswith, aliases)
+
+                if any(where):
+                    if sum(where) != 1:
+                        raise AssertionError(
+                            'Ambiguous parameter aliases "{0}" passed, valid '
+                            'parameter aliases are '
+                            '{1}'.format([n for n, m in zip(aliases, where)
+                                          if m], self._AXIS_ALIASES))
+
+                    k = aliases[where.index(True)]
+
+                    try:
+                        kwargs[self._AXIS_ALIASES[k]] = kwargs.pop(k)
+                    except KeyError:
+                        raise KeyError('Invalid parameter alias '
+                                       '"{0}"'.format(k))
+                else:
+                    try:
+                        kwargs[a] = args.pop(0)
+                    except IndexError:
+                        raise ValueError(
+                            "not enough arguments specified to transpose!")
 
         axes = [self._get_axis_number(kwargs[a]) for a in self._AXIS_ORDERS]
 

pandas/tests/test_panel.py

@@ -1140,6 +1140,30 @@ def test_transpose(self):
         expected = self.panel.swapaxes('items', 'minor')
         assert_panel_equal(result, expected)
 
+        # test kwargs
+        result = self.panel.transpose(items='minor', major='major',
+                                      minor='items')
+        expected = self.panel.swapaxes('items', 'minor')
+        assert_panel_equal(result, expected)
+
+        # text mixture of args
+        result = self.panel.transpose('minor', major='major', minor='items')
+        expected = self.panel.swapaxes('items', 'minor')
+        assert_panel_equal(result, expected)
+
+        result = self.panel.transpose('minor', 'major', minor='items')
+        expected = self.panel.swapaxes('items', 'minor')
+        assert_panel_equal(result, expected)
+
+        ## test bad aliases
+        # test ambiguous aliases
+        self.assertRaises(AssertionError, self.panel.transpose, 'minor',
+                          maj='major', majo='items')
+
+        # test invalid kwargs
+        self.assertRaises(KeyError, self.panel.transpose, 'minor',
+                          maj='major', minor='items')
+
         result = self.panel.transpose(2, 1, 0)
         assert_panel_equal(result, expected)