Clojure

Other Clojure solutions.

(ns word-count
  (:require [clojure.string :refer [split lower-case]]))

(defn word-count [s]
  (let [words (split (lower-case s) #" ")
        grouped-words (group-by identity words)]
    (zipmap
     (keys grouped-words)
     (map count (vals grouped-words)))))

Elixir

Other Elixir solutions.

defmodule WordCount do
  @doc """
  Count the number of words in the sentence.

  Words are compared case-insensitively.
  """
  @spec count(String.t()) :: map
  def count(sentence) do
    sentence
    |> String.downcase()
    |> String.split([" ", "_"])
    |> Enum.map(&sanitize(&1))
    |> Enum.filter(fn a -> String.length(a) > 0 end)
    |> group_as_map
  end

  defp sanitize(str) do
    str
    |> String.trim()
    |> String.replace(~r/[^-\w]/iu, "")
  end

  defp group_as_map(list_str) do
    list_str
    |> Enum.group_by(fn a -> a end)
    |> Enum.map(fn {k, v} -> {k, length(v)} end)
    |> Enum.into(%{})
  end
end

Roc

Other Roc solutions.

module [countWords]

countWords : Str -> Dict Str U64
countWords = \sentence ->
    sentence
    |> Str.replaceEach "," " "
    |> Str.split " "
    |> List.map sanitizeWord
    |> List.dropIf Str.isEmpty
    |> List.walk (Dict.empty {}) \dict, word ->
        Dict.update dict word \result ->
            when result is
                Ok existing -> Ok (existing + 1)
                Err Missing -> Ok 1

sanitizeWord : Str -> Str
sanitizeWord = \word ->
    word
    |> Str.trim
    |> Str.dropPrefix "'"
    |> Str.dropSuffix "'"
    |> Str.toUtf8
    |> List.map \char -> if char >= 'A' && char <= 'Z' then char + 32 else char
    |> List.keepIf \char -> (char >= 'a' && char <= 'z') || (char >= '0' && char <= '9') || char == '\''
    |> Str.fromUtf8
    |> Result.withDefault ""