Error message is unhelpful when rank_targets is called with a bad target

[tdsmith]

In [6]: eleven.rank_targets(df, ["ACTB", "B2M", "GAPDH"], "BM9")
...
IndexError: cannot do a non-empty take from an empty axes.

In [11]: any(df["Target"] == "GAPDH")
Out[11]: False

[bmiles]

bit lost hitting this @tdsmith

ranked = eleven.rank_targets(censored, '18s', 'Control')
...
IndexError: cannot do a non-empty take from an empty axes.

any(censored["Target"] == "18s")
...
True

[tdsmith]

Hi Ben! Sorry to say I haven't touched this in long enough that I'm not sure I remember what this means either. :) It's a pretty embarrassing codebase. I can take a look this weekend, which will probably shame me into redoing the API.

[bmiles]

hehe no problem, I saw the last commit was some time ago, please don't go to any effort!