Grade School - Adding Same Student Twice

[czrpb]

Hi!

I just did Grade School and my add ended up like 20lines long, with a filter and reduce! 🤯

I reviewed the community solutions and I noticed that pretty much none of them would handle adding the same student to the same grade twice, ie: test #11: Most dont remove dups in the grade roster, they just blindly add.

This caused me to poke into this test further and I found that the current "example" solution:

elixir/exercises/practice/grade-school/.meta/example.ex

Lines 2 to 8 in 1a1cec4

	def add(db, name, grade) do
	if name in List.flatten(Map.values(db)) do
	db
	else
	Map.update(db, grade, [name], &[name | &1])
	end
	end

is deficient when the order of adds in this test is reverse (and why my attempt is so long!):

elixir/exercises/practice/grade-school/test/school_test.exs

Lines 20 to 27 in 1a1cec4

	test "a student cannot be added to more than one grade" do
	actual =
	@db
	|> School.add("Aimee", 2)
	|> School.add("Aimee", 1)
	assert actual == %{2 => ["Aimee"]}
	end

I'd like to:

1. duplicate this test but with the add order reversed
2. update the "example", though maybe after someone reviews my solution! there has got to be a better one?!? 😁

Should I continue this?

thx!! << q

[angelikatyborska]

Hi!

I am not sure I understand the problem.

When I add a second test but with a reverse order of adds, the example solution still passes. Those are the tests that I'm using:

  test "a student cannot be added to more than one grade 1" do
    actual =
      @db
      |> School.add("Aimee", 2)
      |> School.add("Aimee", 1)

    assert actual == %{2 => ["Aimee"]}
  end

  test "a student cannot be added to more than one grade 2" do
    actual =
      @db
      |> School.add("Aimee", 1)
      |> School.add("Aimee", 2)

    assert actual == %{1 => ["Aimee"]}
  end

Can you try to explain in more detail what's wrong?

I reviewed the community solutions and I noticed that pretty much none of them would handle adding the same student to the same grade twice

This is because this test case was added recently.

[jiegillet]

Just FYI, there is movement over here to change the specifications of this exercise. Might be worth waiting a bit.

[czrpb]

hi!

OMG! 1st, so sorry: im an old genx coder in the corp world for 20+ yrs so forgive my lack of norms in the "open-source" community! 😜

So, the problem, I made an assumption: You would want to be able to "move" students to the next grade, thus I wrote the reordered test as:

test "a student cannot be added to more than one grade 2" do
    actual =
      @db
      |> School.add("Aimee", 1)
      |> School.add("Aimee", 2)

    assert actual == %{2 => ["Aimee"]}
  end

I made the assumption that when adding a student the end result is that they should be in the greatest/latest class' roster. Thus my solution required removing from a old grade (and removing that grade if the roster is empty) and adding to the newer.

Therefore, I think I read too much into the problem/requirements. 😆

Thoughts on now? Should I just close this?

thx!!

[angelikatyborska]

I see! It's just much simpler than that 🙂 no worries.

I'll close the issue.