IndexError using converters in read_html

[Amaelb]

read_html returns a list of DF. Giving a converters parameter (see #13461) applies the converters on each DF. Keys of the converters, when being integers, can not be greater than the number of columns minus 1 of the parsed DF (otherwise it raises an IndexError exception in io.parser.PythonParser._convert_data ).
But most of the time, DFs returned by read_html are of different sizes. Thus converters are unusable on all columns of index greater min([len(df.column) for df in pd.read_html(url)])

Example

import pandas

def converter_one(c):
    return 1

d = {0 : converter_one, 1 : converter_one}
d2 = {0 : converter_one, 1 : converter_one, 2 : converter_one}
url = 'https://web.archive.org/web/20160419075502/http://clients.rte-france.com/lang/an/visiteurs/vie/prod/prevision_production.jsp'
pandas.read_html(url, converters = d2)

Expected Output

As in

pandas.read_html(url, converters = d)

This issue may also prevent to change read_htmlas proposed in #14608

Output of pd.show_versions()

INSTALLED VERSIONS

commit: None
python: 3.5.2.final.0
python-bits: 64
OS: Darwin
OS-release: 15.6.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: None
LANG: fr_FR.UTF-8
LOCALE: fr_FR.UTF-8

pandas: 0.19.1
nose: 1.3.7
pip: 8.1.2
setuptools: 23.0.0
Cython: 0.25.1
numpy: 1.11.2
scipy: 0.17.1
statsmodels: 0.6.1
xarray: None
IPython: 4.2.0
sphinx: 1.4.1
patsy: 0.4.1
dateutil: 2.5.3
pytz: 2016.7
blosc: None
bottleneck: 1.1.0
tables: 3.2.2
numexpr: 2.6.0
matplotlib: 1.5.1
openpyxl: 2.3.2
xlrd: 1.0.0
xlwt: 1.1.2
xlsxwriter: 0.9.2
lxml: 3.6.0
bs4: 4.4.1
html5lib: 1.0b8
httplib2: None
apiclient: None
sqlalchemy: 1.0.13
pymysql: None
psycopg2: None
jinja2: 2.8
boto: 2.40.0
pandas_datareader: None

[mroeschke]

Looks like this example is no longer reproducible. Happy to reopen this issue if we can get a reproducible example.

In [9]: import pandas
   ...:
   ...: def converter_one(c):
   ...:     return 1
   ...:
   ...: d = {0 : converter_one, 1 : converter_one}
   ...: d2 = {0 : converter_one, 1 : converter_one, 2 : converter_one}
   ...: url = 'http://clients.rte-france.com/lang/an/visiteurs/vie/prod/prevision_production.jsp'
   ...: pandas.read_html(url, converters = d2)

ValueError: No tables found

[Amaelb]

changing url to

url = 'https://web.archive.org/web/20160419075502/http://clients.rte-france.com/lang/an/visiteurs/vie/prod/prevision_production.jsp'

makes it work again.

[paulcwatts]

This is a minimal reproduction:

import pandas as pd

pd.read_html(
    """
<table>
<tbody>
  <tr>
    <td>Foo</td>
  </tr>
</tbody>
</table>
""",
    converters={1: lambda x: x},
)

The backtrace:

Traceback (most recent call last):
  File line 3, in <module>
    pd.read_html(
  File "/usr/local/lib/python3.10/site-packages/pandas/util/_decorators.py", line 311, in wrapper
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.10/site-packages/pandas/io/html.py", line 1098, in read_html
    return _parse(
  File "/usr/local/lib/python3.10/site-packages/pandas/io/html.py", line 931, in _parse
    ret.append(_data_to_frame(data=table, **kwargs))
  File "/usr/local/lib/python3.10/site-packages/pandas/io/html.py", line 811, in _data_to_frame
    return tp.read()
  File "/usr/local/lib/python3.10/site-packages/pandas/io/parsers/readers.py", line 1047, in read
    index, columns, col_dict = self._engine.read(nrows)
  File "/usr/local/lib/python3.10/site-packages/pandas/io/parsers/python_parser.py", line 283, in read
    data = self._convert_data(data)
  File "/usr/local/lib/python3.10/site-packages/pandas/io/parsers/python_parser.py", line 321, in _convert_data
    clean_conv = _clean_mapping(self.converters)
  File "/usr/local/lib/python3.10/site-packages/pandas/io/parsers/python_parser.py", line 317, in _clean_mapping
    col = self.orig_names[col]
IndexError: list index out of range