set_option as a context manager

[jseabold]

It doesn't look like it's available yet as such, but it might be nice to have set_option usable as a context manager. E.g., I often find myself wanting to do something like

with pd.set_option('max_rows', 200):
    print df

As simple as adding __enter__ and __exit__ methods and preserving state?

[jreback]

you have to do something like:

with pd.option_context('max_rows',200):
      print df

IIRC

[jseabold]

Oh nice. Is it new? I don't see it in the namespace. Probably deserves a mention in the set_option docstring too.

[jreback]

I think it's been around
mostly for internal use
let's make this issue a doc issue then

[jseabold]

config_prefix according to #2097. And it's not exposed at the top-level namespace AFAICT.

[ghost]

option_context: #2516, and it was extended later to accept multiple key/value pairs, I think at cpcloud's suggestion.

so you can

with option_context(foo,"is1", bar, "is2"):
    baz

[jseabold]

Ah, great. Then consider this a request for importing it into the top-level namespace and adding some docs.

[ghost]

I have no objections to that. Can't remember the details but I think the reason set_option
itself isn't a context_manager was that it clashed with the nifty dynamic docstring
magic attached to it, which no one ever noticed or used. Should probably just ditch that
and make set_option a context manager instead. More intuitive.
Can just calculate the docstring once at the end of config_init and set it instead
of all that fuffing around in config.py.

[ghost]

Thanks @jseabold.

[oztalha]

Running this in a Jupyter notebook shell does not print anythin:

with pd.option_context('display.max_colwidth', -1):
    HTML(guesses.to_html(escape=False))

but this does work as expected:

pd.set_option('display.max_colwidth', -1)
HTML(guesses.to_html(escape=False))

I expected to get the same result but I did not. Any ideas, why? Is it a problem on the Jupyter side or re the implementation of the context? Thanks.

[TomAugspurger]

@oztalha wrap your HTML(...) in an IPython.display.display. The notebook won't treat the version inside the context manager as a "return value" to be displayed.

[oztalha]

Thanks, worked just as you said:

with pd.option_context('display.max_colwidth', -1):
    display(HTML(guesses.to_html(escape=False)))