CODEWITHSUNDEEP
elixir
Rasanjana N
Rasanjana N

Reputation: 1400

Iterate through Enum and extract values

list_of_comboboxes=[
{"option", [{"value", ""}, {"selected", "selected"}], ["Select Color"]}, 
{"option", [{"value", "White"}, {"data", "White"}], ["White"]},
{"option", [{"value", "Red"}, {"data", "Red"}], ["Red"]},
{"option", [{"value", "Black"}, {"data", "Black"}], ["Black"]}
]

Need to extract all the values in the above Enum to a list

Upvotes: 1

Views: 703

Answers (4)

Aleksei Matiushkin
Aleksei Matiushkin

Reputation: 121010

Just out of curiosity #2:

defmodule M do
  def extract({"option", [{"value", value} | _], _}), do: value
end
Enum.map(list_of_comboboxes, &M.extract/1)
#⇒ ["", "White", "Red", "Black"]

This might look worse, but in fact it gives more flexibility: one might adjust the implementation details (M.extract/1) leaving the integration code (Enum.map) intact.

That way the code stays more modular. E.g. one might use the List.keyfind/3 proposed by @Dogbert in M.extract/1 for better interoperability, while the main code stays as it was.

Upvotes: 1

Aleksei Matiushkin
Aleksei Matiushkin

Reputation: 121010

Just out of curiosity:

list_of_comboboxes
|> Enum.map(fn {"option", list, _} ->
     Enum.map(list, fn {k, v} -> {String.to_atom(k), v} end)[:value]
   end)
#⇒ ["", "White", "Red", "Black"]

Upvotes: 3

GavinBrelstaff
GavinBrelstaff

Reputation: 3069

list_of_comboboxes |>
Enum.map( fn ({_, [{_, x}, {_, _}], [_]}) -> 
          x end )

Upvotes: 2

Dogbert
Dogbert

Reputation: 222378

Here's one way to do this using pattern matching, for, and List.keyfind/3:

iex(1)> list_of_comboboxes=[
...(1)>   {"option", [{"value", ""}, {"selected", "selected"}], ["Select Color"]},
...(1)>   {"option", [{"value", "White"}, {"data", "White"}], ["White"]},
...(1)>   {"option", [{"value", "Red"}, {"data", "Red"}], ["Red"]},
...(1)>   {"option", [{"value", "Black"}, {"data", "Black"}], ["Black"]}
...(1)> ]
iex(2)> for {_, list, _} <- list_of_comboboxes,
...(2)>     {"value", value} = List.keyfind(list, "value", 0),
...(2)>     do: value
["", "White", "Red", "Black"]

This will work even if {"value", value} is not the first item of the list.

Upvotes: 2

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