Allow index as column name in table widgets (#2990)

* Allow index as column name in table widgets

* Handle unnamed indexes

panel/tests/widgets/test_tables.py

@@ -207,6 +207,19 @@ def test_hierarchical_index(document, comm):
     assert isinstance(agg2, MinAggregator)
 
 
+def test_table_index_column(document, comm):
+    df = pd.DataFrame({
+        'int': [1, 2, 3],
+        'float': [3.14, 6.28, 9.42],
+        'index': ['A', 'B', 'C'],
+    }, index=[1, 2, 3])
+    table = DataFrame(value=df)
+
+    model = table.get_root(document, comm=comm)
+
+    assert np.array_equal(model.source.data['level_0'], np.array([1, 2, 3]))
+    assert model.columns[0].field == 'level_0'
+    assert model.columns[0].title == ''
 
 
 def test_none_table(document, comm):
@@ -288,6 +301,21 @@ def test_tabulator_expanded_content():
     assert row2.text == "<pre>2.0</pre>"
 
 
+def test_tabulator_index_column(document, comm):
+    df = pd.DataFrame({
+        'int': [1, 2, 3],
+        'float': [3.14, 6.28, 9.42],
+        'index': ['A', 'B', 'C'],
+    }, index=[1, 2, 3])
+    table = Tabulator(value=df)
+
+    model = table.get_root(document, comm=comm)
+
+    assert np.array_equal(model.source.data['level_0'], np.array([1, 2, 3]))
+    assert model.columns[0].field == 'level_0'
+    assert model.columns[0].title == ''
+
+
 def test_tabulator_expanded_content_pagination():
     df = makeMixedDataFrame()
 

panel/widgets/tables.py

@@ -184,6 +184,8 @@ def _get_column_definitions(self, col_names, df):
             title = self.titles.get(col, str(col))
             if col in indexes and len(indexes) > 1 and self.hierarchical:
                 title = 'Index: %s' % ' | '.join(indexes)
+            elif col in self.indexes and col.startswith('level_'):
+                title = ''
             column = TableColumn(field=str(col), title=title,
                                  editor=editor, formatter=formatter,
                                  **col_kwargs)
@@ -409,9 +411,13 @@ def _get_data(self):
         if df is None:
             return [], {}
         if isinstance(self.value.index, pd.MultiIndex):
-            indexes = list(df.index.names)
+            indexes = [
+                f'level_{i}' if n is None else n
+                for i, n in enumerate(df.index.names)
+            ]
         else:
-            indexes = [df.index.name or 'index']
+            default_index = ('level_0' if 'index' in df.columns else 'index')
+            indexes = [df.index.name or default_index]
         if len(indexes) > 1:
             df = df.reset_index()
         data = ColumnDataSource.from_df(df)
@@ -432,8 +438,12 @@ def indexes(self):
         if self.value is None or not self.show_index:
             return []
         elif isinstance(self.value.index, pd.MultiIndex):
-            return list(self.value.index.names)
-        return [self.value.index.name or 'index']
+            return [
+                f'level_{i}' if n is None else n
+                for i, n in enumerate(self.value.index.names)
+            ]
+        default_index = ('level_0' if 'index' in self.value.columns else 'index')
+        return [self.value.index.name or default_index]
 
     def stream(self, stream_value, rollover=None, reset_index=True):
         """
@@ -990,9 +1000,13 @@ def _get_data(self):
         start = (self.page-1)*nrows
         page_df = df.iloc[start: start+nrows]
         if isinstance(self.value.index, pd.MultiIndex):
-            indexes = list(df.index.names)
+            indexes = [
+                f'level_{i}' if n is None else n
+                for i, n in enumerate(df.index.names)
+            ]
         else:
-            indexes = [df.index.name or 'index']
+            default_index = ('level_0' if 'index' in df.columns else 'index')
+            indexes = [df.index.name or default_index]
         if len(indexes) > 1:
             page_df = page_df.reset_index()
         data = ColumnDataSource.from_df(page_df).items()