CODEWITHSUNDEEP
elixirphoenix-framework
Cristian Garcia
Cristian Garcia

Reputation: 9859

Get elements from a list by their type of struct in Elixir

I have a params map and want to get the list of values who's "type" is %Plug.Upload{}. How do I check for the type in Elixir?

Upvotes: 3

Views: 1182

Answers (3)

Dogbert
Dogbert

Reputation: 222198

You can use the pattern %Plug.Upload{} with for as for skips all the items that do not match the passed pattern.

This will return a list of all the files present in the values of the Map params:

for {_, %Plug.Upload{} = file} <- params, do: file

If you just want to do something with the file, you can pass a block to do:

for {_, %Plug.Upload{} = file} <- params do
  IO.inspect file
end

Change _ to a variable name if you also want to access the file's name as present in the form that was submitted.

Upvotes: 0

user2793784
user2793784

Reputation: 71

params is a map, so Enum.filter gets key/value pairs, and the value is what will be a Plug.Upload, so:

params |> Enum.filter(fn({k, v}) -> match?(%Plug.Upload{}, v) end)

Upvotes: 0

Paweł Obrok
Paweł Obrok

Reputation: 23174

You can pattern match on structs just as you can on maps, so you can use Enum.filter and Kernel.match?:

params
|> Enum.filter(&match?(%Plug.Upload{}, &1))

Upvotes: 4

Related Questions