fixup! ENH: Added to_json_schema

Author: TomAugspurger

pandas/io/json/table_schema.py

@@ -5,6 +5,7 @@
 """
 from collections import OrderedDict
 
+from pandas.compat import string_types
 from pandas.types.common import (
     is_integer_dtype, is_timedelta64_dtype, is_numeric_dtype,
     is_bool_dtype, is_datetime64_dtype, is_datetime64tz_dtype,
@@ -78,7 +79,17 @@ def _set_default_names(data):
 
 def _make_field(arr, dtype=None):
     dtype = dtype or arr.dtype
-    field = OrderedDict([("name", arr.name or 'values'),
+    if arr.name is None:
+        name = 'values'
+    elif isinstance(arr.name, string_types):
+        name = arr.name
+    elif hasattr(arr.name, 'isoformat'):
+        # Timestamps / Timedeltas aren't
+        name = arr.name.isoformat()
+    else:
+        name = arr.name
+
+    field = OrderedDict([("name", name),
                          ('type', _as_json_table_type(dtype))])
     if is_categorical_dtype(arr):
         if hasattr(arr, 'categories'):
@@ -166,9 +177,8 @@ def build_table_schema(data, index=True, primary_key=None, version=True):
 
     schema['fields'] = fields
     if index and data.index.is_unique and primary_key is None:
-        # TODO: Always a list, spec allows for a string scalar.
         if data.index.nlevels == 1:
-            schema['primaryKey'] = data.index.name
+            schema['primaryKey'] = [data.index.name]
         else:
             schema['primaryKey'] = data.index.names
     elif primary_key is not None:

pandas/io/tests/json/test_json_table_schema.py renamed to pandas/tests/io/json/test_json_table_schema.py

@@ -33,7 +33,7 @@ def test_build_table_schema(self):
                        {'name': 'C', 'type': 'datetime'},
                        {'name': 'D', 'type': 'duration'},
                        ],
-            'primaryKey': 'idx'
+            'primaryKey': ['idx']
         }
         self.assertEqual(result, expected)
         result = build_table_schema(self.df)
@@ -44,7 +44,7 @@ def test_series(self):
         result = build_table_schema(s, version=False)
         expected = {'fields': [{'name': 'index', 'type': 'integer'},
                                {'name': 'foo', 'type': 'integer'}],
-                    'primaryKey': 'index'}
+                    'primaryKey': ['index']}
         self.assertEqual(result, expected)
         result = build_table_schema(s)
         self.assertTrue('pandas_version' in result)
@@ -53,7 +53,7 @@ def tets_series_unnamed(self):
         result = build_table_schema(pd.Series([1, 2, 3]), version=False)
         expected = {'fields': [{'name': 'index', 'type': 'integer'},
                                {'name': 'values', 'type': 'integer'}],
-                    'primaryKey': 'index'}
+                    'primaryKey': ['index']}
         self.assertEqual(result, expected)
 
     def test_multiindex(self):
@@ -197,7 +197,7 @@ def test_build_series(self):
                   OrderedDict([('name', 'a'), ('type', 'integer')])]
         schema = OrderedDict([
             ('fields', fields),
-            ('primaryKey', 'id'),
+            ('primaryKey', ['id']),
         ])
 
         expected = OrderedDict([
@@ -236,7 +236,7 @@ def test_to_json(self):
 
         schema = OrderedDict([
             ('fields', fields),
-            ('primaryKey', 'idx'),
+            ('primaryKey', ['idx']),
         ])
         data = [
             OrderedDict([('idx', 0), ('A', 1), ('B', 'a'),
@@ -280,7 +280,7 @@ def test_to_json_float_index(self):
                                                       ('type', 'number')]),
                                          OrderedDict([('name', 'values'),
                                                       ('type', 'integer')])]),
-                                       ('primaryKey', 'index')])),
+                                       ('primaryKey', ['index'])])),
                          ('data',
                           [OrderedDict([('index', 1.0), ('values', 1)]),
                            OrderedDict([('index', 2.0), ('values', 1)])])])
@@ -302,7 +302,7 @@ def test_to_json_period_index(self):
                                                       ('freq', 'Q-JAN')]),
                                          OrderedDict([('name', 'values'),
                                                       ('type', 'integer')])]),
-                                       ('primaryKey', 'index')])),
+                                       ('primaryKey', ['index'])])),
                          ('data', [
                              OrderedDict([('index',
                                            '2015-11-01T00:00:00.000Z'),
@@ -330,7 +330,7 @@ def test_to_json_categorical_index(self):
                                                       ('ordered', False)]),
                                          OrderedDict([('name', 'values'),
                                                       ('type', 'integer')])]),
-                                       ('primaryKey', 'index')])),
+                                       ('primaryKey', ['index'])])),
                          ('data', [
                              OrderedDict([('index', 'a'),
                                           ('values', 1)]),
@@ -418,7 +418,7 @@ def test_categorical(self):
 
         expected = OrderedDict([
             ('schema', OrderedDict([
-                ('fields', fields), ('primaryKey', 'idx')])),
+                ('fields', fields), ('primaryKey', ['idx'])])),
             ('data', [OrderedDict([('idx', 0), ('values', 'a')]),
                       OrderedDict([('idx', 1), ('values', 'b')]),
                       OrderedDict([('idx', 2), ('values', 'a')])])])
@@ -453,3 +453,11 @@ def test_set_default_names_mi_partion(self):
                                           names=['n1', None]))
         result = _set_default_names(data)
         self.assertEqual(result.index.names, ['n1', 'level_1'])
+
+    def test_timestamp_in_columns(self):
+        df = pd.DataFrame([[1, 2]], columns=[pd.Timestamp('2016'),
+                                             pd.Timedelta(10, unit='s')])
+        result = df.to_json(orient="table")
+        js = json.loads(result)
+        assert js['schema']['fields'][1]['name'] == '2016-01-01T00:00:00'
+        assert js['schema']['fields'][2]['name'] == 'P0DT0H0M10S'