prevent the pandas.Categorical support breaking support for older versions of pandas

njsmith · njsmith · commit 48d4eeef240c · 2013-02-09T18:14:48.000-08:00
diff --git a/patsy/build.py b/patsy/build.py
@@ -12,7 +12,8 @@
 from patsy import PatsyError
 from patsy.categorical import CategoricalTransform, Categorical
 from patsy.util import (atleast_2d_column_default,
-                           have_pandas, asarray_or_pandas)
+                        have_pandas, have_pandas_categorical,
+                        asarray_or_pandas)
 from patsy.design_info import DesignMatrix, DesignInfo
 from patsy.redundancy import pick_contrasts_for_term
 from patsy.desc import ModelDesc
@@ -441,7 +442,8 @@ def _examine_factor_types(factors, factor_states, data_iter_maker):
             break
         for factor in list(examine_needed):
             value = factor.eval(factor_states[factor], data)
-            if have_pandas and isinstance(value, pandas.Categorical):
+            if (have_pandas_categorical
+                and isinstance(value, pandas.Categorical)):
                 value = Categorical.from_pandas_categorical(value)
                 # fall through into the next 'if':
             if isinstance(value, Categorical):
diff --git a/patsy/categorical.py b/patsy/categorical.py
@@ -9,7 +9,8 @@
 from patsy import PatsyError
 from patsy.state import stateful_transform
 from patsy.util import (SortAnythingKey,
-                        have_pandas, asarray_or_pandas,
+                        have_pandas, have_pandas_categorical,
+                        asarray_or_pandas,
                         pandas_friendly_reshape)
 
 if have_pandas:
@@ -214,7 +215,7 @@ def memorize_finish(self):
 
     def transform(self, data, contrast=None, levels=None):
         kwargs = {"contrast": contrast}
-        if have_pandas and isinstance(data, pandas.Categorical):
+        if have_pandas_categorical and isinstance(data, pandas.Categorical):
             data = Categorical.from_pandas_categorical(data)
             # fall through to the next 'if':
         if isinstance(data, Categorical):
@@ -295,7 +296,7 @@ def test_C_pandas():
         assert cat3.contrast == "asdf"
 
 def test_categorical_from_pandas_categorical():
-    if have_pandas:
+    if have_pandas_categorical:
         pandas_categorical = pandas.Categorical.from_array(["a", "b", "a"])
         c = Categorical.from_pandas_categorical(pandas_categorical)
         assert np.array_equal(c.int_array, [0, 1, 0])
diff --git a/patsy/test_build.py b/patsy/test_build.py
@@ -10,7 +10,8 @@
 import numpy as np
 from nose.tools import assert_raises
 from patsy import PatsyError
-from patsy.util import atleast_2d_column_default, have_pandas
+from patsy.util import (atleast_2d_column_default,
+                        have_pandas, have_pandas_categorical)
 from patsy.compat import itertools_product
 from patsy.desc import Term, INTERCEPT, LookupFactor
 from patsy.build import *
@@ -437,7 +438,7 @@ def test_categorical():
     data_strings = {"a": ["a1", "a2", "a1"]}
     data_categ = {"a": C(["a2", "a1", "a2"])}
     datas = [data_strings, data_categ]
-    if have_pandas:
+    if have_pandas_categorical:
         data_pandas = {"a": pandas.Categorical.from_array(["a1", "a2", "a2"])}
         datas.append(data_pandas)
     def t(data1, data2):
diff --git a/patsy/util.py b/patsy/util.py
@@ -22,6 +22,11 @@
 else:
     have_pandas = True
 
+# Pandas versions < 0.9.0 don't have Categorical
+# Can drop this guard whenever we drop support for such older versions of
+# pandas.
+have_pandas_categorical = (have_pandas and hasattr(pandas, "Categorical"))
+
 # Passes through Series and DataFrames, call np.asarray() on everything else
 def asarray_or_pandas(a, copy=False, dtype=None, subok=False):
     if have_pandas:
