read_html: support "decimal" argument for parsing numbers, like read_csv

[educhana]

read_csv has support for declaring the decimal and thousands separator.

read_html is missing the 'decimal' parameter. it'd be useful and more consistent to accept it too.

Example:

pd.read_html(html, thousands='.', decimal=',')

[jreback]

this is a dupe of #8200 but we'll close that issue. This should be straightforward and just need to pass this thru to the parser. Pull-requests are welcome.

[sldion]

I don't think that TextParser supports passing the decimal keyword in python. The functionality probably needs to be added to PythonParser

[jreback]

This defaults to the c-engine, so I don't really see a problem. If it actually is, then you could defer to the python engine if the decimal kw is not-None.

#12933 to add the decimal option (I don't know if we have that particular issue).

Alternatively, you could post-process.

In [7]: s = Series(['1,2','2,3'])

In [8]: s
Out[8]: 
0    1,2
1    2,3
dtype: object

In [9]: pd.to_numeric(s.str.replace(',','.'),errors='coerce')
Out[9]: 
0    1.2
1    2.3
dtype: float64