issue_comments: 238053642

I'm conflicted about how to handle the repr. On the one hand, I like how * indicates indexable variables. On the other hand, it should indeed be clear that these are MultiIndex levels, not dimensions in their own right (especially if they don't appear in ds.coords.keys() and the like). So maybe something closer to what we had before would be better.

Let me try to sketch out some concrete proposals to encourage the peanut gallery to speak up:

Option 1: no special indicator for the MultiIndex:

Coordinates: * level_1 (x) object 'a' 'a' 'b' 'b' * level_2 (x) int64 0 1 0 1 * y (y) int64 0 1 2 3

Option 2: both MultiIndex and levels in repr:

Coordinates: * x (x) MultiIndex * level_1 (x) object 'a' 'a' 'b' 'b' * level_2 (x) int64 0 1 0 1 * y (y) int64 0 1 2 3

Option 3: both MultiIndex and levels in repr, different symbol for levels:

Coordinates: * x (x) MultiIndex - level_1 (x) object 'a' 'a' 'b' 'b' - level_2 (x) int64 0 1 0 1 * y (y) int64 0 1 2 3

Option 4: both MultiIndex and levels in repr, different symbol for levels, with indentation:

Coordinates: * x (x) MultiIndex - level_1 (x) object 'a' 'a' 'b' 'b' - level_2 (x) int64 0 1 0 1 * y (y) int64 0 1 2 3

A separate question (if we pick one of options 2-4) is how to represent the MultiIndex dtype and values (everything after the dimension name):

Option A: MultiIndex (as shown above) Option B: MultiIndex[level_0, level_1] Option C: object MultiIndex Option D: object MultiIndex[level_0, level_1] Option E: MultiIndex ('a', 0) ('a', 1) ('b', 0) ('b', 1) Option F: object ('a', 0) ('a', 1) ('b', 0) ('b', 1) (current repr)

The tradeoffs here are whether or not we include the exact dtype information (object), and how explicitly/redundantly we display the values.

I'm currently leaning toward Option 3A, but I don't have a strong opinion.