Merge pull request #960 from VisLab/develop

replace_na to rid future warning

hed/tools/remodeling/operations/factor_hed_tags_op.py

@@ -2,13 +2,13 @@
 
 
 import pandas as pd
-import numpy as np
 from hed.tools.remodeling.operations.base_op import BaseOp
 from hed.models.tabular_input import TabularInput
 from hed.models.sidecar import Sidecar
 from hed.models import query_service
 from hed.tools.analysis.event_manager import EventManager
 from hed.tools.analysis.hed_tag_manager import HedTagManager
+from hed.tools.util.data_util import replace_na
 
 
 class FactorHedTagsOp(BaseOp):
@@ -126,7 +126,7 @@ def do_op(self, dispatcher, df, name, sidecar=None):
         if len(df_factors.columns) > 0:
             df_list.append(df_factors)
         df_new = pd.concat(df_list, axis=1)
-        df_new.replace('n/a', np.nan, inplace=True)
+        replace_na(df_new)
         return df_new
 
     @staticmethod

hed/tools/remodeling/operations/factor_hed_type_op.py

@@ -1,11 +1,11 @@
 """ Append to columnar file the factors computed from type variables. """
 
 import pandas as pd
-import numpy as np
 from hed.tools.remodeling.operations.base_op import BaseOp
 from hed.models.tabular_input import TabularInput
 from hed.tools.analysis.event_manager import EventManager
 from hed.tools.analysis.hed_type_manager import HedTypeManager
+from hed.tools.util.data_util import replace_na
 
 
 class FactorHedTypeOp(BaseOp):
@@ -82,7 +82,7 @@ def do_op(self, dispatcher, df, name, sidecar=None):
         if len(df_factors.columns) > 0:
             df_list.append(df_factors)
         df_new = pd.concat(df_list, axis=1)
-        df_new.replace('n/a', np.nan, inplace=True)
+        replace_na(df_new)
         return df_new
 
     @staticmethod

hed/tools/util/data_util.py

@@ -211,6 +211,15 @@ def make_info_dataframe(col_info, selected_col):
     df = pd.DataFrame(sorted(list(col_values)), columns=[selected_col])
     return df
 
+def replace_na(df):
+    """ Replace (in place) the n/a with np.nan taking care of categorical columns.  """
+    for column in df.columns:
+        if df[column].dtype.name != 'category':
+            df[column] = df[column].replace('n/a', np.nan)
+        elif 'n/a' in df[column].cat.categories:
+            df[column] = df[column].astype('object')
+            df[column] = df[column].replace('n/a', np.nan)
+            df[column] = pd.Categorical(df[column])
 
 def replace_values(df, values=None, replace_value='n/a', column_list=None):
     """ Replace string values in specified columns.

tests/tools/util/test_data_util.py

@@ -1,11 +1,12 @@
 import os
 import unittest
 import numpy as np
-from pandas import DataFrame
+
+from pandas import DataFrame, Categorical
 from hed.errors.exceptions import HedFileError
 from hed.tools.util.data_util import add_columns, check_match, delete_columns, delete_rows_by_column, \
     get_key_hash, get_new_dataframe, get_row_hash, get_value_dict, \
-    make_info_dataframe, reorder_columns, replace_values, separate_values
+    make_info_dataframe, reorder_columns, replace_na, replace_values, separate_values
 
 
 class Test(unittest.TestCase):
@@ -107,6 +108,43 @@ def test_make_info_dataframe(self):
         df2 = make_info_dataframe(col_dict, "Baloney")
         self.assertFalse(df2, "make_frame should return None if column name invalid")
 
+    def test_replace_na(self):
+        # With categorical column containing n/a's
+        df = DataFrame({
+            'A': Categorical(['apple', 'n/a', 'cherry']),
+            'B': ['n/a', 'pear', 'banana']
+        })
+        replace_na(df)
+        self.assertTrue(df['A'].isnull().any())
+        self.assertTrue(df['B'].isnull().any())
+
+        # With categorical column not containing n/a's
+        df = DataFrame({
+            'A': Categorical(['apple', 'orange', 'cherry']),
+            'B': ['pear', 'melon', 'banana']
+        })
+        replace_na(df)
+        self.assertFalse(df['A'].isnull().any())
+        self.assertFalse(df['B'].isnull().any())
+
+        # preserving other values
+        df = DataFrame({
+            'A': Categorical(['apple', 'n/a', 'cherry']),
+            'B': ['n/a', 'pear', 'banana'],
+            'C': [1, 2, 3]
+        })
+        replace_na(df)
+        self.assertEqual(list(df['C']), [1, 2, 3])
+
+        # Non-categorical n/a replacement
+        df = DataFrame({
+            'A': ['apple', 'n/a', 'cherry'],
+            'B': ['n/a', 'pear', 'banana']
+        })
+        replace_na(df)
+        self.assertTrue(df['A'].isnull().any())
+        self.assertTrue(df['B'].isnull().any())
+
     def test_replace_values(self):
         data = {'Name': ['n/a', '', 'tom', 'alice', 0, 1],
                 'Age': [np.nan, 10, '', 'n/a', '0', '10']}