display.display_html has no effect in Jupyter notebook

[pwaller]

Versions:

• IPython 4.0.3
• Jupyter 1.0.0

Example code:

import IPython.display
IPython.display.display_html("<b>foo bar</b>")

What happens when I run this cell? No visible output.

What is expected? It should show the words "foo bar" in bold.

What works? IPython.display.display(IPython.display.HTML("<b>foo bar</b>")).

Am I doing the right thing here? How do I just show an object formatted as HTML? I want to show several objects in one cell execution, so just putting the object as the last thing in the cell isn't sufficient.

The documentation seems to imply this should work.

[minrk]

display_html displays the HTML representations of an object. That is, it looks up registered display methods, such as _repr_html_, and calls them, displaying the result, if any. str objects do not have an HTML representation, so nothing is displayed.

If you want to publish raw HTML as a string, then what you want is to pass raw=True, which seems to be what you are after:

import IPython.display
IPython.display.display_html("<b>foo bar</b>", raw=True)

[pwaller]

Thanks @minrk for the quick response. Is there scope for me to send a PR to improve the display documentation to mention this caveat? It wasn't clear to me that this is what was happening, even after searching around for a good 30 minutes.

[pwaller]

Another kind of fix (even better than the docs with respect to discovering mistakes) would be to show some kind of indication that there was nothing to show.

[minrk]

Definitely feel free to open a PR clarifying the docs, that would be very welcome.

[takluyver]

Maybe the display_x functions should throw an error if the object passed to them doesn't have an x representation? I would have been confused by that.

[pwaller]

I would be in favour of that.