Implementing init for PersistentVector

fsprojects · May 29, 2012 · da0a771 · da0a771
1 parent 5f2e9cd
commit da0a771
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Showing 2 changed files with 16 additions and 2 deletions.
diff --git a/src/FSharpx.Core/DataStructures/Vector.fs b/src/FSharpx.Core/DataStructures/Vector.fs
@@ -449,4 +449,10 @@ let inline map (f:'a -> 'b) (vector:'a vector) : 'b vector =
     let mutable ret = TransientVector()
     for item in vector do
         ret <- ret.conj(f item)
-    ret.persistent() :> 'b vector
+    ret.persistent() :> 'b vector
+
+let inline init count (f: int -> 'a) : 'a vector =
+    let mutable ret = TransientVector()
+    for i in 0..(count-1) do
+        ret <- ret.conj(f i)
+    ret.persistent() :> 'a vector
diff --git a/tests/FSharpx.DataStructures.Tests/PersistentVectorTest.fs b/tests/FSharpx.DataStructures.Tests/PersistentVectorTest.fs
@@ -138,4 +138,12 @@ let ``vector should allow map``() =
 
     let vector2 = map (fun x -> x * 2) (!vector)
 
-    vector2 |> Seq.toList |> should equal [for i in 1..30000 -> i * 2]
+    vector2 |> Seq.toList |> should equal [for i in 1..30000 -> i * 2]
+
+[<Test>]
+let ``vector should allow init``() =
+    let vector = init 5 (fun x -> x * 2) 
+    let s = Seq.init 5 (fun x -> x * 2)
+
+    s |> Seq.toList |> should equal [0;2;4;6;8]
+    vector |> Seq.toList |> should equal [0;2;4;6;8]