add shorthand to filter out nan values from array #249

fslaborg · Feb 28, 2023 · 6b83908 · 6b83908
1 parent 4780203
commit 6b83908
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Showing 3 changed files with 18 additions and 1 deletion.
diff --git a/src/FSharp.Stats/Array.fs b/src/FSharp.Stats/Array.fs
@@ -500,4 +500,10 @@ module Array =
     let inline covBy f (array: 'T array) : 'U =
         array
         |> Array.map f
-        |> covOfPairs
+        |> covOfPairs
+
+    /// Filters out all nan values from an array
+    let dropNaN (array: float array) =
+        array 
+        |> Array.filter (System.Double.IsNaN >> not)
+
diff --git a/tests/FSharp.Stats.Tests/Array.fs b/tests/FSharp.Stats.Tests/Array.fs
@@ -39,3 +39,13 @@ let medianTests =
             let median = Array.median testArrayOddCountsInt
             Expect.equal median 5 "Median should be 5"
     ]
+
+[<Tests>]
+let dropNanTests =
+    testList "Array" [
+        testCase "dropNaN" <| fun () ->
+            let testArray = [|-infinity; 0.5; 1.5; 1000.; nan; 5.0; nan|]
+            let expected = [|-infinity; 0.5; 1.5; 1000.; 5.0|]
+            let actual = Array.dropNaN testArray
+            Expect.equal expected actual "Filtered array is incorrect"
+    ]
diff --git a/tests/FSharp.Stats.Tests/Main.fs b/tests/FSharp.Stats.Tests/Main.fs
@@ -34,6 +34,7 @@ let main argv =
 
     //================================== Array ==============================================================
     Tests.runTestsWithCLIArgs [] argv ArrayTests.medianTests   |> ignore
+    Tests.runTestsWithCLIArgs [] argv ArrayTests.dropNanTests   |> ignore
 
     //================================== Interval ===========================================================
     Tests.runTestsWithCLIArgs [] argv IntervalTests.intervalTests   |> ignore