How to find index of element inside enum by property? I have this enum and I need to find the index of an item by its id(or another property). [%{“code” => “ABEV3”, “comparison” => “>”, “field” => “close”, “id” => “4a9d96ce-e572-11eb-a557-0242ac170003”, “message” => “ABEV3 Close price is higher th…

Sorry I most likely confused you with the hint that map-items are given as {k, v} to the function. You have a list of maps, So you just do: e = [%{foo: :bar, id: 1}, %{foo: :baz, id: 2}, %{foo: :foobar, id: 3}] iex(3)> Enum.find_index(e, fn v -> v.id == 1 end) 0 So find…

see: Enum.find_index/2 EDIT: OP did not post a map. Note, that your map-items will be passed as {key, value} to the function. See the example at the beginning of the Enum documentation: map = %{"a" => 1, "b" => 2} Enum.map(map, fn {k, v} -> {k, v * 2} end) [{"a", 2}, {"b", 4}]

Didn’t get it… I understand that I can use find when I already have the element, like this / Enum.find(alerts, fn x -> equal?(x, alert) end) |> case do nil -> alerts idx -> List.delete_at(alerts, idx) end But when I want to find it by the property, I’m not being able to, tryed …

But the question is how to find by property… The examples show how to find by equality, I currently don’t have the entire object, only the property(id) value

You want to (eg) find the index of the item with id==2 right? [%{id: 1, foo: :bar}, %{id: 2, foo: :baz}, %{id: 3, foo: :foobar}] So you want the index of {id: 2, foo: baz} which is 1…? Edit: too much python today.

find_index/2 will return the index of the first element, where the function you provide returns true. So write that function.

Don`t like python, but C, C#, Javascript… I’m just new to Elixir, and didn’t spend enough time to learn it yet, but thank you for your help

take a look at the great visual Elixir reference: find_index/2 Elixir Enum.find_index/2 function. Graphical representation of the Elixir's Enum.find_index/2 function

you can also use pattern matching Enum.find_index(list, fn %{id: ^id} -> true; _ -> false end) you could also use filter to just remove the item Enum.filter(list, fn %{id: ^id} -> false; _ -> true end)

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Enum find by id?

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Sebb July 15, 2021, 4:00pm 4

Sorry I overlooked that you want the index. I updated my answer.