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to Pangram in the Elm Track

Published at Jul 12 2019 · 0 comments
Test suite

Determine if a sentence is a pangram. A pangram (Greek: παν γράμμα, pan gramma, "every letter") is a sentence using every letter of the alphabet at least once. The best known English pangram is:

The quick brown fox jumps over the lazy dog.

The alphabet used consists of ASCII letters a to z, inclusive, and is case insensitive. Some input will contain non-ASCII symbols.

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!


Wikipedia https://en.wikipedia.org/wiki/Pangram

Submitting Incomplete Solutions

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


module Tests exposing (tests)

import Expect
import Pangram exposing (isPangram)
import Test exposing (..)

tests : Test
tests =
    describe "Pangram"
        [ test "sentence empty" <|
            \() ->
                Expect.equal False
                    (isPangram "")
        , skip <|
            test "pangram with only lower case" <|
                \() ->
                    Expect.equal True
                        (isPangram "the quick brown fox jumps over the lazy dog")
        , skip <|
            test "missing character 'x'" <|
                \() ->
                    Expect.equal False
                        (isPangram "a quick movement of the enemy will jeopardize five gunboats")
        , skip <|
            test "missing character 'z'" <|
                \() ->
                    Expect.equal False
                        (isPangram "a quick movement of the enemy will jeopardixe five gunboats")
        , skip <|
            test "another missing character 'x'" <|
                \() ->
                    Expect.equal False
                        (isPangram "the quick brown fish jumps over the lazy dog")
        , skip <|
            test "pangram with underscores" <|
                \() ->
                    Expect.equal True
                        (isPangram "the_quick_brown_fox_jumps_over_the_lazy_dog")
        , skip <|
            test "pangram with numbers" <|
                \() ->
                    Expect.equal True
                        (isPangram "the 1 quick brown fox jumps over the 2 lazy dogs")
        , skip <|
            test "missing letters replaced by numbers" <|
                \() ->
                    Expect.equal False
                        (isPangram "7h3 qu1ck brown fox jumps ov3r 7h3 lazy dog")
        , skip <|
            test "pangram with mixed case and punctuation" <|
                \() ->
                    Expect.equal True
                        (isPangram "\"Five quacking Zephyrs jolt my wax bed.\"")
        , skip <|
            test "pangram with non ascii characters" <|
                \() ->
                    Expect.equal True
                        (isPangram "Victor jagt zwölf Boxkämpfer quer über den großen Sylter Deich.")
module Pangram exposing (isPangram)

import Set

isPangram : String -> Bool
isPangram sentence =
        numberOfLettersInAlphabet =
        |> String.toLower
        |> String.filter Char.isAlpha
        |> String.toList
        |> Set.fromList
        |> Set.size
        |> (==) numberOfLettersInAlphabet

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