Created method to retrieve the wavelength lines from NIST.

[b1quint]

Created method to handle what was requested on Issue #28.

This method uses BeautifulSoup4 instead of HTMLParser. It also uses NumPy and Pandas.

[tepickering]

looks like pandas needs to be added to the travis dependency list...and BeautifulSoup...

[bsipocz]

use specreduce here rather than dummy

[b1quint]

Three tests still fail when trying to import pandas. I modified the setup.cfg and the .rtd-environment.yml files to include pandas and beautifulsoup4. I am trying to find where else should I add them to have all tests passing.

[bsipocz]

@b1quint - If they are dependencies, the they should be added to the travis config file into the CONDA_DEPENDENCIES env variable

[b1quint]

\o/

[tepickering]

i'll restate my comment from #29 here: a disadvantage of returning DataFrames is the lack of any units metadata. pandas will likely not have any units support for a while as well (pandas-dev/pandas#15698). i think it's much more preferable to attach explicit units metadata to wavelengths than rely on a convention. this is why astropy.units was created, after all. there might be a way to hack the metadata into the DataFrame, but i think it's a lot more straightforward to use Quantity arrays or Qtable. They are also much more compatible with the rest of the astropy stack.

[bsipocz]

I think this package should use astroquery to access the NIST database rather than reinvent and implement the wheel. If any functionality is missing from astroquery, contribute it to there.

https://astroquery.readthedocs.io/en/latest/nist/nist.html

[tepickering]

i completely agree! had no idea NIST was already implemented in astroquery....

[bsipocz]

Not just NIST, but also a few other ones (that may not be relevant here, though): https://astroquery.readthedocs.io/en/latest/#other

[b1quint]

If this is the case, I will just close this Pull Request. Is that ok?