BUG: TypeError with to_html(sparsify=False) and max_cols < len(columns) (#24572)

Author: simonjayhawkins

doc/source/whatsnew/v0.24.0.rst

@@ -1604,6 +1604,7 @@ Notice how we now instead output ``np.nan`` itself instead of a stringified form
 - Bug in :func:`to_html()` with ``index=False`` when both columns and row index are ``MultiIndex`` (:issue:`22579`)
 - Bug in :func:`to_html()` with ``index_names=False`` displaying index name (:issue:`22747`)
 - Bug in :func:`to_html()` with ``header=False`` not displaying row index names (:issue:`23788`)
+- Bug in :func:`to_html()` with ``sparsify=False`` that caused it to raise ``TypeError`` (:issue:`22887`)
 - Bug in :func:`DataFrame.to_string()` that broke column alignment when ``index=False`` and width of first column's values is greater than the width of first column's header (:issue:`16839`, :issue:`13032`)
 - Bug in :func:`DataFrame.to_string()` that caused representations of :class:`DataFrame` to not take up the whole window (:issue:`22984`)
 - Bug in :func:`DataFrame.to_csv` where a single level MultiIndex incorrectly wrote a tuple. Now just the value of the index is written (:issue:`19589`).

pandas/io/formats/html.py

@@ -241,7 +241,7 @@ def _write_col_header(self, indent):
                 # GH3547
                 sentinel = com.sentinel_factory()
             else:
-                sentinel = None
+                sentinel = False
             levels = self.columns.format(sparsify=sentinel, adjoin=False,
                                          names=False)
             level_lengths = get_level_lengths(levels, sentinel)
@@ -440,9 +440,6 @@ def _write_hierarchical_rows(self, fmt_values, indent):
         truncate_v = self.fmt.truncate_v
         frame = self.fmt.tr_frame
         nrows = len(frame)
-        # TODO: after gh-22887 fixed, refactor to use class property
-        # in place of row_levels
-        row_levels = self.frame.index.nlevels
 
         idx_values = frame.index.format(sparsify=False, adjoin=False,
                                         names=False)
@@ -520,18 +517,24 @@ def _write_hierarchical_rows(self, fmt_values, indent):
 
                 row.extend(fmt_values[j][i] for j in range(self.ncols))
                 if truncate_h:
-                    row.insert(row_levels - sparse_offset +
+                    row.insert(self.row_levels - sparse_offset +
                                self.fmt.tr_col_num, '...')
                 self.write_tr(row, indent, self.indent_delta, tags=tags,
                               nindex_levels=len(levels) - sparse_offset)
         else:
+            row = []
             for i in range(len(frame)):
+                if truncate_v and i == (self.fmt.tr_row_num):
+                    str_sep_row = ['...'] * len(row)
+                    self.write_tr(str_sep_row, indent, self.indent_delta,
+                                  tags=None, nindex_levels=self.row_levels)
+
                 idx_values = list(zip(*frame.index.format(
                     sparsify=False, adjoin=False, names=False)))
                 row = []
                 row.extend(idx_values[i])
                 row.extend(fmt_values[j][i] for j in range(self.ncols))
                 if truncate_h:
-                    row.insert(row_levels + self.fmt.tr_col_num, '...')
+                    row.insert(self.row_levels + self.fmt.tr_col_num, '...')
                 self.write_tr(row, indent, self.indent_delta, tags=None,
                               nindex_levels=frame.index.nlevels)

pandas/tests/io/formats/data/html/truncate_multi_index_sparse_off.html

@@ -57,6 +57,17 @@
       <td>NaN</td>
       <td>NaN</td>
     </tr>
+    <tr>
+      <th>...</th>
+      <th>...</th>
+      <td>...</td>
+      <td>...</td>
+      <td>...</td>
+      <td>...</td>
+      <td>...</td>
+      <td>...</td>
+      <td>...</td>
+    </tr>
     <tr>
       <th>foo</th>
       <th>two</th>

pandas/tests/io/formats/test_to_html.py

@@ -223,7 +223,6 @@ def test_to_html_truncate_multi_index(self, datapath):
         expected = expected_html(datapath, 'truncate_multi_index')
         assert result == expected
 
-    @pytest.mark.xfail(reason='GH22887 TypeError')
     def test_to_html_truncate_multi_index_sparse_off(self, datapath):
         arrays = [['bar', 'bar', 'baz', 'baz', 'foo', 'foo', 'qux', 'qux'],
                   ['one', 'two', 'one', 'two', 'one', 'two', 'one', 'two']]