Documentation Error - pandas2ri causes ModuleNotFoundError

[webartifex]

Code Sample, a copy-pastable example if possible

Compare
https://pandas.pydata.org/pandas-docs/version/0.23.3/r_interface.html
with
https://pandas.pydata.org/pandas-docs/version/0.23.4/r_interface.html

from rpy2.robjects import pandas2ri
...

Problem description

The import generates a ModuleNotFoundError

[WillAyd]

Not a pandas issue as rpy2 is a separate project, though the error points to that not even being installed

[WillAyd]

Sorry misread your issue - I see you are referring to the pandas docs and not an attempt to do this locally.

[webartifex]

I believe there is still a bug, but most likely it is in the rpy2 package.

When I install rpy2 version 2.8.* this ModuleNotFoundError does NOT occur.

However, with the latest 2.9.* release it does occur.

Explicitly pip installing the tzlocal package seems to fix it.

I conclude that tzlocal is not installed together with rpy2.

Maybe someone wants to confirm this behavior?

[jorisvandenbossche]

There is already an issue at rpy2: https://bitbucket.org/rpy2/rpy2/issues/458/tzlocal-dependency

Apparently, tzlocal is an optional dependency of rpy2 (just as pandas is as well), so the user (i.e. we, for the docs) is responsible to make sure to install it.

[TomAugspurger]

The docs are built with a this environment: https://github.com/pandas-dev/pandas/blob/master/ci/travis-36-doc.yaml

@webartifex can you make a PR adding tzlocal to that environment?