BUG: read_html(extract_links=all) with no header (#48334)

Author: mroeschke

pandas/io/html.py

@@ -34,6 +34,7 @@
 from pandas import isna
 from pandas.core.construction import create_series_with_explicit_dtype
 from pandas.core.indexes.base import Index
+from pandas.core.indexes.multi import MultiIndex
 
 from pandas.io.common import (
  file_exists,
@@ -1009,9 +1010,11 @@ def _parse(flavor, io, match, attrs, encoding, displayed_only, extract_links, **
  try:
  df = _data_to_frame(data=table, **kwargs)
  # Cast MultiIndex header to an Index of tuples when extracting header
- # links and replace nan with None.
+ # links and replace nan with None (therefore can't use mi.to_flat_index()).
  # This maintains consistency of selection (e.g. df.columns.str[1])
- if extract_links in ("all", "header"):
+ if extract_links in ("all", "header") and isinstance(
+ df.columns, MultiIndex
+ ):
  df.columns = Index(
  ((col[0], None if isna(col[1]) else col[1]) for col in df.columns),
  tupleize_cols=False,

pandas/tests/io/test_html.py

@@ -1416,3 +1416,18 @@ def test_extract_links_bad(self, spam_data):
  )
  with pytest.raises(ValueError, match=msg):
  read_html(spam_data, extract_links="incorrect")
+
+ def test_extract_links_all_no_header(self):
+ # GH 48316
+ data = """
+ <table>
+ <tr>
+ <td>
+ <a href='https://google.com'>Google.com</a>
+ </td>
+ </tr>
+ </table>
+ """
+ result = self.read_html(data, extract_links="all")[0]
+ expected = DataFrame([[("Google.com", "https://google.com")]])
+ tm.assert_frame_equal(result, expected)