csain · October 15, 2018 19:55 · Oct 15, 2018
diff --git a/Sample.elm b/Sample.elm
@@ -0,0 +1,34 @@
+-- Given a list of items and a seed int (such as a current timestamp), sample an item from a list.
+
+module Helpers.Sample exposing (sample)
+
+import List.Extra
+import Random
+import Tuple
+
+
+randomInt : { min : Int, max : Int, seed : Int } -> Int
+randomInt { min, max, seed } =
+    -- This function returns a pseudorandom integer within a range based on a seed
+    -- Random.initialSeed creates a reproducable sequence of pseudorandom values
+    -- Random.int returns a 'Generator Int' within a range [min, max]
+    -- Random.step returns an (a, Seed) where 'a' is a generator type
+    Random.step (Random.int min max) (Random.initialSeed seed)
+        |> Tuple.first
+
+
+sample : List a -> Int -> Maybe a
+sample items seed =
+    -- Sample a random item from a list
+    -- by choosing a random index within the range of the length of the list
+    let
+        index : Int
+        index =
+            randomInt
+                { min = 0
+                , max = List.length items - 1
+                , seed = seed
+                }
+    in
+    items
+        |> List.Extra.getAt index
No results found