Making the str equivalent of the dimensionless_unscaled unit more discoverable

We’re using astropy.unit in a context where we want every value to be an astropy Quantity. We’re also serializing definitions of the things we’re measuring in YAML, so we’re making heavy use of the string representations of astropy Units. Some of these things have intrinsically dimensionless_unscaled units, so we’re seeing a lot of:

unit: ''

in our YAML files. While unit: 'mmag' → Unit('mmag') is easy to understand, my colleagues have asked a lot of questions about these “empty string” units.

So I’m wondering if we can improve the UX of the string representations of dimensionless_unscaled units a bit. I have two ideas:

• Make the string 'dimensionless_unscaled' an alias for the string '' so that we can write 'dimensionless_unscaled' in text serializations of Units.
• Improve the discoverability of the dimensionless_unscaled in the documentation. Most units are featured in a nice table on the package page (http://docs.astropy.org/en/stable/units/index.html) but dimensionless_unscaled is only explicitly mentioned on a deeper topic page (http://docs.astropy.org/en/stable/units/standard_units.html#the-dimensionless-unit) and even then its string representation is only mentioned in passing.

What does astropy think about these proposals? I’m happy to turn this into a PR if one or both of these ideas seem useful.

[tcjansen]

@pllim - Yes, I actually had a similar confusion with the documentation recently so I’d be happy to give it a shot!

[jonathansick]

Thanks @pllim, I didn’t realized that Unit('1') also worked, not just Unit(1). It’d be worth adding that to the “documentation improvement” aspect of this issue.