Merge pull request #51 from tgecho/nucleotide-count-records

Convert nucleotide-counts to use a record rather than a `List (Char, Int)`

exercises/nucleotide-count/NucleotideCount.example

@@ -1,18 +1,16 @@
 module NucleotideCount (..) where
 
 import String
-import List
 
 
-nucleotideCounts : String -> List ( Char, Int )
+nucleotideCounts : String -> { a : Int, t : Int, c : Int, g : Int }
 nucleotideCounts sequence =
-  [ (getCount 'A' sequence)
+  let
-  , (getCount 'T' sequence)
+    getCount n =
-  , (getCount 'C' sequence)
+      String.filter (\c -> c == n) sequence |> String.length
-  , (getCount 'G' sequence)
+  in
-  ]
+    { a = getCount 'A'
-
+    , t = getCount 'T'
-
+    , c = getCount 'C'
-getCount : Char -> String -> ( Char, Int )
+    , g = getCount 'G'
-getCount base sequence =
+    }
-  ( base, (List.length (String.split (String.fromChar base) sequence)) - 1 )

exercises/nucleotide-count/NucleotideCountTests.elm

@@ -13,19 +13,19 @@ tests =
     [ test
         "empty dna strand has no nucleotides"
         (assertEqual
-          [ ( 'A', 0 ), ( 'T', 0 ), ( 'C', 0 ), ( 'G', 0 ) ]
+          { a = 0, t = 0, c = 0, g = 0 }
           (nucleotideCounts "")
         )
     , test
         "repetitive-sequence-has-only-guanosine"
         (assertEqual
-          [ ( 'A', 0 ), ( 'T', 0 ), ( 'C', 0 ), ( 'G', 8 ) ]
+          { a = 0, t = 0, c = 0, g = 8 }
           (nucleotideCounts "GGGGGGGG")
         )
     , test
         "counts all nucleotides"
         (assertEqual
-          [ ( 'A', 20 ), ( 'T', 21 ), ( 'C', 12 ), ( 'G', 17 ) ]
+          { a = 20, t = 21, c = 12, g = 17 }
           (nucleotideCounts "AGCTTTTCATTCTGACTGCAACGGGCAATATGTCTCTGTGTGGATTAAAAAAAGAGTGTCTGATAGCAGC")
         )
     ]