Creating a Dict from a List · beginners

Stream: beginners

Topic: Creating a Dict from a List

Luke Boswell (Oct 25 2022 at 06:39):

Is there a way to create a Dict from a List?

I think this is something I would find very useful particularly for creating expectations to test functions.

Luke Boswell (Oct 25 2022 at 06:43):

Maybe something like

list1 = Dict.fromList [Pair 1 "one", Pair 2 "two"]

# OR

list2 = @Dict [Pair 1 "Keep Me", Pair 2 "And Me"]

Brian Carroll (Oct 25 2022 at 06:46):

Wow yeah we don't appear to have that, I'm surprised! The first form would be more like what we'd support. I'd guess the only reason we don't have it is because we don't have tuple syntax yet so you have to pick a tag name like Pair.
You could do it with a List.walk that starts with Dict.empty and does a Dict.insert in the callback function.

Luke Boswell (Oct 25 2022 at 07:07):

I've been adding examples to the Docs. So i'm currently doing things like this, which works, but maybe could be neater.

first =
    Dict.single 1 "Keep Me"
    |> Dict.insert 2 "And Me"

second =
    Dict.single 1 "Not Me"
    |> Dict.insert 3 "Me Too"
    |> Dict.insert 4 "And Also Me"

expected =
    Dict.single 1 "Keep Me"
    |> Dict.insert 2 "And Me"
    |> Dict.insert 3 "Me Too"
    |> Dict.insert 4 "And Also Me"

expect
    Dict.insertAll first second == expected