diff --git a/src/Data/NumIdr/PrimArray.idr b/src/Data/NumIdr/PrimArray.idr
index f524462..8bd24e3 100644
--- a/src/Data/NumIdr/PrimArray.idr
+++ b/src/Data/NumIdr/PrimArray.idr
@@ -26,6 +26,13 @@ arrayDataSet : Nat -> a -> ArrayData a -> IO ()
 arrayDataSet n x arr = fromPrim $ prim__arraySet arr (cast n) x
 
 
+export
+unsafeFromIns : Nat -> List (Nat, a) -> PrimArray a
+unsafeFromIns size ins = unsafePerformIO $ do
+    arr <- newArrayData size (believe_me ())
+    for_ ins $ \(i,x) => arrayDataSet i x arr
+    pure $ MkPrimArray size arr
+
 export
 create : Nat -> (Nat -> a) -> PrimArray a
 create size f = unsafePerformIO $ do
@@ -40,7 +47,6 @@ create size f = unsafePerformIO $ do
              addToArray (S loc) n arr
 
 
-
 export
 unsafeIndex : Nat -> PrimArray a -> a
 unsafeIndex n arr = unsafePerformIO $ arrayDataGet n $ content arr