Created
February 12, 2023 21:11
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An elm program that calculates the average of input numbers separated by spaces
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module Main exposing (..) | |
import Browser | |
import Html exposing (Html, div, input, text) | |
import Html.Attributes exposing (type_, value) | |
import Html.Events exposing (onInput) | |
-- MAIN | |
main : Program () Model Msg | |
main = | |
Browser.sandbox | |
{ init = init | |
, update = update | |
, view = view | |
} | |
-- MODEL | |
type alias Model = | |
{ grade : String } | |
init : Model | |
init = | |
Model "" | |
-- UPDATE | |
type Msg | |
= UpdateGrade String | |
update : Msg -> Model -> Model | |
update msg model = | |
case msg of | |
UpdateGrade grade -> | |
{ model | grade = grade } | |
-- VIEW | |
view : Model -> Html Msg | |
view model = | |
div [] | |
[ input [ type_ "text", onInput UpdateGrade, value model.grade ] [] | |
, viewGrades (getGrades model.grade) | |
] | |
viewGrades : List Float -> Html Msg | |
viewGrades grades = | |
case average grades of | |
Nothing -> | |
text "No grades" | |
Just float -> | |
text ("Average: " String.fromFloat float) | |
-- HELPER | |
getGrades : String -> List Float | |
getGrades string = | |
List.filterMap String.toFloat (String.words string) | |
average : List Float -> Maybe Float | |
average floats = | |
if List.isEmpty floats then | |
Nothing | |
else | |
Just (List.sum floats / toFloat (List.length floats)) |
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