Grade school exercise will not properly sort grades beyond :grade_9 about elixir HOT 7 CLOSED

Could we not just change :grade_2 to :grade_02?

iex(3)> Enum.sort([:grade_11, :grade_02])
[:grade_02, :grade_11]
iex(4)> Enum.sort([:grade_2, :grade_11]) 
[:grade_11, :grade_2]

Sorry I missed this.

from elixir.

Zero-padding inside a keyword feels like a hack, IMO.

I do like the explicitness of the :grade prefix -- what about using a tagged tuple for the grade?

iex(1)> Enum.sort([{:grade, 11}, {:grade, 2}])
[grade: 2, grade: 11]
iex(2)> Enum.sort([{{:grade, 11}, []}, {{:grade, 2}, []}])
[{{:grade, 2}, []}, {{:grade, 11}, []}]

It's a bit noisy, but (I think) a bit more Erlang-y.

from elixir.

Am I right in thinking this would mean the db is just an ordinary list, rather than a keyword list, and therefore the data in it is only accessible by index or by recursion/map/filter through the list until you get a pattern match on, say, grade? ie.

iex(29)> db |> Enum.filter(fn({{:grade, x}, y}) -> x == 2 end)
[{{:grade, 2}, ["Aimee"]}]  

How would you add multiple people to a grade? It seems to me that that would be a different operation to adding the first person to an empty grade, or to an empty db, unless you had the db structure already in place?

Could a list of maps be used perhaps?

db = [%{1 => ["Aimee"]}, %{2 => ["John", "Matt"]}]

I'm probably missing something, or overthinking this, but I'm having a hard time understanding how you would operate on this if it's not a keyword list or a map. I don't have any Erlang experience, but afaik using a keyword list or a map would be the Elixir-y way to approach the problem?

from elixir.

I think keyword list or map work well for the internal representation of the data, but maybe not as well for the value returned by sort, since it obviously needs to maintain sort order.

from elixir.

Thinking about this again today, I agree with @parkerl that reverting back to using a map but have the sort return a two-tuple list, is probably the best resolution to this. I see what you mean now @rubysolo about separating (& differentiating between) the internal representation of the data and what is returned by a function, such as sort.
I'm happy to make the changes (undo my mistake 😁 ) depending on what you both think.

from elixir.

👍

from elixir.

Closed by #118

from elixir.