Merge pull request #81 from sseyler/aggcategories

Fixes #72.

Fixed behavior of groupby to preserve order of multiple keys

src/datreant/core/agglimbs.py

@@ -572,7 +572,7 @@ def groupby(self, keys):
         corresponding Bundles are groupings of members in the collection having
         the same category values (for the category specied by `keys`).
 
-        If `keys` is a list or set of keys, returns a dict of Bundles whose
+        If `keys` is a list of keys, returns a dict of Bundles whose
         (new) keys are tuples of category values. The corresponding Bundles
         contain the members in the collection that have the same set of
         category values (for the categories specified by `keys`); members in
@@ -581,7 +581,7 @@ def groupby(self, keys):
 
         Parameters
         ----------
-        keys : str, list, set
+        keys : str, list
             Valid key(s) of categories in this collection.
 
         Returns
@@ -603,9 +603,8 @@ def groupby(self, keys):
                    k in m.categories and m.categories[k] in groupkeys)
             for m, catval in gen:
                 groups[catval].add(m)
-
-        elif isinstance(keys, (list, set)):
-            keys = sorted(keys)
+        # Note: redundant code in if/elif block can be consolidated in future
+        elif isinstance(keys, list):
             catvals = list(zip(*members.categories[keys]))
             groupkeys = [v for v in catvals if None not in v]
             groups = {k: Bundle() for k in groupkeys}
@@ -617,6 +616,6 @@ def groupby(self, keys):
                 groups[catvals[i]].add(m)
 
         else:
-            raise TypeError("Keys must be a string or a list or set of"
+            raise TypeError("Keys must be a string or a list of"
                             " strings")
         return groups

src/datreant/core/tests/test_collections.py

@@ -788,17 +788,10 @@ def test_categories_groupby(self, collection, testtreant, testgroup,
                 assert {t3} == set(age_bark[('old', 'mossy')])
                 assert {t4} == set(age_bark[('young', 'mossy')])
 
-                age_bark = collection.categories.groupby({'age', 'bark'})
-                assert len(age_bark) == 4
-                assert {t1} == set(age_bark[('young', 'smooth')])
-                assert {t2} == set(age_bark[('adult', 'fibrous')])
-                assert {t3} == set(age_bark[('old', 'mossy')])
-                assert {t4} == set(age_bark[('young', 'mossy')])
-
                 type_health = collection.categories.groupby(['type', 'health'])
                 assert len(type_health) == 2
-                assert {t3} == set(type_health[('poor', 'deciduous')])
-                assert {t4} == set(type_health[('good', 'deciduous')])
+                assert {t3} == set(type_health[('deciduous', 'poor')])
+                assert {t4} == set(type_health[('deciduous', 'good')])
                 for bundle in type_health.values():
                     assert {t1, t2}.isdisjoint(set(bundle))
 
@@ -826,29 +819,25 @@ def test_categories_groupby(self, collection, testtreant, testgroup,
                 keys = ['age', 'bark', 'type', 'nickname']
                 abtn = collection.categories.groupby(keys)
                 assert len(abtn) == 1
-                assert {t2} == set(abtn[('adult', 'fibrous', 'redwood',
-                                         'evergreen')])
+                assert {t2} == set(abtn[('adult', 'fibrous', 'evergreen',
+                                         'redwood')])
                 for bundle in abtn.values():
                     assert {t1, t3, t4}.isdisjoint(set(bundle))
 
                 keys = ['bark', 'nickname', 'type', 'age']
                 abtn2 = collection.categories.groupby(keys)
                 assert len(abtn2) == 1
-                assert {t2} == set(abtn2[('adult', 'fibrous', 'redwood',
-                                          'evergreen')])
+                assert {t2} == set(abtn2[('fibrous', 'redwood', 'evergreen',
+                                          'adult')])
                 for bundle in abtn2.values():
                     assert {t1, t3, t4}.isdisjoint(set(bundle))
 
-                keys = {'age', 'bark', 'type', 'nickname'}
-                abtn_set = collection.categories.groupby(keys)
-                assert len(abtn_set) == 1
-                assert {t2} == set(abtn_set[('adult', 'fibrous', 'redwood',
-                                             'evergreen')])
-                for bundle in abtn_set.values():
-                    assert {t1, t3, t4}.isdisjoint(set(bundle))
-
                 keys = ['health', 'nickname']
                 health_nick = collection.categories.groupby(keys)
                 assert len(health_nick) == 0
                 for bundle in health_nick.values():
                     assert {t1, t2, t3, t4}.isdisjoint(set(bundle))
+
+                # Test key TypeError in groupby
+                with pytest.raises(TypeError) as e:
+                    collection.categories.groupby({'health', 'nickname'})