explodeString - Interview question of the week from rendezvous with cassidoo

I’m doing some work in Elixir now, so I figure I’d take a shot at this week’s question with Elixir.

Interview question of the week

This week’s question: Given a string, separate it into groups of non-space equal characters, sorted.

Example:

> explodeString('Ahh, abracadabra!')
> ['!',',','A','aaaaa','bb','c','d','hh','rr']

> explodeString('\o/\o/')
> ['//','\\','oo']

My solution

My solution is still what I’d expect it to look like in any other language with a reasonable collections API. The Map.update/4 is a nice signature for handling both new keys as well as existing keys.

defmodule Example do
    def explode_string(str) do
        str
        |> String.replace(~r/\s+/, "")
        |> String.to_charlist()
        |> Enum.reduce(%{}, fn c, m ->
            Map.update(m, c, [c], fn a ->
                [c | a]
            end)
        end)
        |> Map.values()
        |> Enum.sort()
    end
end