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epequeno's solution

to Anagram in the Elm Track

Published at Apr 24 2021 · 0 comments
Instructions
Test suite
Solution

An anagram is a rearrangement of letters to form a new word. Given a word and a list of candidates, select the sublist of anagrams of the given word.

Given "listen" and a list of candidates like "enlists" "google" "inlets" "banana" the program should return a list containing "inlets".

Elm Installation

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

Writing the Code

The code you have to write is located inside the src/ directory of the exercise. Elm automatically installs packages dependencies the first time you run the tests so we can start by running the tests from the exercise directory with:

$ elm-test

To automatically run tests again when you save changes:

$ elm-test --watch

As you work your way through the tests suite in the file tests/Tests.elm, be sure to remove the skip <| calls from each test until you get them all passing!

Source

Inspired by the Extreme Startup game https://github.com/rchatley/extreme_startup

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 Anagram exposing (detect)
import Expect
import Test exposing (..)


tests : Test
tests =
    describe "Anagram"
        [ test "no matches" <|
            \() ->
                Expect.equal []
                    (detect "diaper" [ "hello", "world", "zombies", "pants" ])
        , skip <|
            test "detects simple anagram" <|
                \() ->
                    Expect.equal [ "tan" ]
                        (detect "ant" [ "tan", "stand", "at" ])
        , skip <|
            test "does not detect false positives" <|
                \() ->
                    Expect.equal []
                        (detect "galea" [ "eagle" ])
        , skip <|
            test "detects multiple anagrams" <|
                \() ->
                    Expect.equal [ "stream", "maters" ]
                        (detect "master" [ "stream", "pigeon", "maters" ])
        , skip <|
            test "does not detect anagram subsets" <|
                \() ->
                    Expect.equal []
                        (detect "good" [ "dog", "goody" ])
        , skip <|
            test "detects anagram" <|
                \() ->
                    Expect.equal [ "inlets" ]
                        (detect "listen" [ "enlists", "google", "inlets", "banana" ])
        , skip <|
            test "detects even more anagrams" <|
                \() ->
                    Expect.equal [ "gallery", "regally", "largely" ]
                        (detect "allergy" [ "gallery", "ballerina", "regally", "clergy", "largely", "leading" ])
        , skip <|
            test "does not detect identical words" <|
                \() ->
                    Expect.equal [ "cron" ]
                        (detect "corn" [ "corn", "dark", "Corn", "rank", "CORN", "cron", "park" ])
        , skip <|
            test "does not detect non-anagrams with identical checksum" <|
                \() ->
                    Expect.equal []
                        (detect "mass" [ "last" ])
        , skip <|
            test "detects anagrams case-insensitively" <|
                \() ->
                    Expect.equal [ "Carthorse" ]
                        (detect "Orchestra" [ "cashregister", "Carthorse", "radishes" ])
        , skip <|
            test "detects anagrams using case-insensitive subject" <|
                \() ->
                    Expect.equal [ "carthorse" ]
                        (detect "Orchestra" [ "cashregister", "carthorse", "radishes" ])
        , skip <|
            test "detects anagrams using case-insensitive possible matches" <|
                \() ->
                    Expect.equal [ "Carthorse" ]
                        (detect "orchestra" [ "cashregister", "Carthorse", "radishes" ])
        , skip <|
            test "does not detect a word as its own anagram" <|
                \() ->
                    Expect.equal []
                        (detect "banana" [ "Banana" ])
        , skip <|
            test "does not detect a anagram if the original word is repeated" <|
                \() ->
                    Expect.equal []
                        (detect "go" [ "go Go GO" ])
        , skip <|
            test "anagrams must use all letters exactly once (go)" <|
                \() ->
                    Expect.equal []
                        (detect "tapper" [ "patter" ])
        , skip <|
            test "eliminates anagrams with the same checksum" <|
                \() ->
                    Expect.equal []
                        (detect "mass" [ "last" ])
        , skip <|
            test "detects unicode anagrams" <|
                \() ->
                    Expect.equal [ "ΒΓΑ", "γβα" ]
                        (detect "ΑΒΓ" [ "ΒΓΑ", "ΒΓΔ", "γβα" ])
        , skip <|
            test "eliminates misleading unicode anagrams" <|
                \() ->
                    Expect.equal []
                        (detect "ΑΒΓ" [ "ABΓ" ])
        , skip <|
            test "capital word is not own anagram" <|
                \() ->
                    Expect.equal []
                        (detect "BANANA" [ "Banana" ])
        , skip <|
            test "anagrams must use all letters exactly once (banana)" <|
                \() ->
                    Expect.equal []
                        (detect "patter" [ "tapper" ])
        ]
module Anagram exposing (detect)


detect : String -> List String -> List String
detect word candidates =
    candidates
        |> List.filter
            (\c ->
                (sorted c == sorted word)
                    && (String.toLower c /= String.toLower word)
            )


sorted : String -> String
sorted =
    String.toLower
        >> String.toList
        >> List.sort
        >> String.fromList

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