Avatar of maj313

maj313's solution

to Word Count in the Elm Track

Published at Sep 01 2019 · 0 comments
Instructions
Test suite
Solution

Given a phrase, count the occurrences of each word in that phrase.

For example for the input "olly olly in come free"

olly: 2
in: 1
come: 1
free: 1

Elm Installation

Refer to the Installing Elm page for information about installing elm.

Writing the Code

The first time you start an exercise, you'll need to ensure you have the appropriate dependencies installed. Thankfully, Elm makes that easy for you and will install dependencies when you try to run tests or build the code.

Execute the tests with:

$ elm-test

Automatically run tests again when you save changes:

$ elm-test --watch

As you work your way through the test suite, be sure to remove the skip <| calls from each test until you get them all passing!

Source

This is a classic toy problem, but we were reminded of it by seeing it in the Go Tour.

Submitting Incomplete Solutions

It is possible to submit an incomplete solution so you can see how others have completed the exercise.

Tests.elm

module Tests exposing (tests)

import Dict exposing (Dict)
import Expect
import Test exposing (..)
import WordCount exposing (wordCount)


tests : Test
tests =
    describe "Word Count"
        [ test "count one word" <|
            \() ->
                Expect.equal [ ( "word", 1 ) ]
                    (wordCount "word" |> Dict.toList)
        , skip <|
            test "count one of each word" <|
                \() ->
                    Expect.equal [ ( "each", 1 ), ( "of", 1 ), ( "one", 1 ) ]
                        (wordCount "one of each" |> Dict.toList)
        , skip <|
            test "multiple occurrences of a word" <|
                \() ->
                    Expect.equal [ ( "blue", 1 ), ( "fish", 4 ), ( "one", 1 ), ( "red", 1 ), ( "two", 1 ) ]
                        (wordCount "one fish two fish red fish blue fish" |> Dict.toList)
        , skip <|
            test "ignore punctuation" <|
                \() ->
                    Expect.equal [ ( "as", 1 ), ( "car", 1 ), ( "carpet", 1 ), ( "java", 1 ), ( "javascript", 1 ) ]
                        (wordCount "car : carpet as java : javascript!!&@$%^&" |> Dict.toList)
        , skip <|
            test "include numbers" <|
                \() ->
                    Expect.equal [ ( "1", 1 ), ( "2", 1 ), ( "testing", 2 ) ]
                        (wordCount "testing, 1, 2 testing" |> Dict.toList)
        , skip <|
            test "normalize case" <|
                \() ->
                    Expect.equal [ ( "go", 3 ), ( "stop", 2 ) ]
                        (wordCount "go Go GO Stop stop" |> Dict.toList)
        ]
module WordCount exposing (wordCount, sanitize)

import Dict exposing (Dict)
import Dict.Extra exposing (frequencies)
import List.Extra exposing (getAt)


wordCount : String -> Dict String Int
wordCount sentence =
    String.toLower sentence
        |> String.words
        |> sanitize
        |> Dict.Extra.frequencies


sanitize : List String -> List String
sanitize stringList =
    case stringList of
        head :: tail ->
            if  sanitizeHelper head == "" then
                  sanitize tail
                    |> List.append []

            else
                sanitize tail
                  |> List.append (sanitizeHelper head :: [])

        [] ->
            []


sanitizeHelper : String -> String
sanitizeHelper string =
    if (String.contains "'" string)  then
      let
          gl = String.split "'" string
          gsA = case (List.Extra.getAt 0 gl) of
                    Just v -> String.filter Char.isAlphaNum v
                    Nothing -> ""
          gsB = case (List.Extra.getAt 1 gl) of
                    Just v -> String.filter Char.isAlphaNum v
                    Nothing -> ""

      in
          gsA ++ "'" ++ gsB

    else
        String.filter (Char.isAlphaNum) string

Community comments

Find this solution interesting? Ask the author a question to learn more.

What can you learn from this solution?

A huge amount can be learned from reading other people’s code. This is why we wanted to give exercism users the option of making their solutions public.

Here are some questions to help you reflect on this solution and learn the most from it.

  • What compromises have been made?
  • Are there new concepts here that you could read more about to improve your understanding?