Add partition to Data.Array

Author: raichoo

src/Data/Array.js

@@ -174,6 +174,21 @@ exports.filter = function (f) {
   };
 };
 
+exports.partition = function (f) {
+  return function (xs) {
+    var yes = [];
+    var no  = [];
+    for (var i = 0; i < xs.length; i++) {
+      var x = xs[i];
+      if (f(x))
+        yes.push(x);
+      else
+        no.push(x);
+    }
+    return {yes: yes, no: no};
+  };
+};
+
 //------------------------------------------------------------------------------
 // Sorting ---------------------------------------------------------------------
 //------------------------------------------------------------------------------

src/Data/Array.purs

@@ -64,6 +64,7 @@ module Data.Array
   , concat
   , concatMap
   , filter
+  , partition
   , filterM
   , mapMaybe
   , catMaybes
@@ -369,6 +370,13 @@ concatMap = flip bind
 -- | creating a new array.
 foreign import filter :: forall a. (a -> Boolean) -> Array a -> Array a
 
+-- | Partition an array using a predicate function, creating a set of
+-- | new arrays. One for the values satisfying the predicate function
+-- | and one for values that don't.
+foreign import partition :: forall a. (a -> Boolean)
+                         -> Array a
+                         -> { yes :: Array a, no :: Array a }
+
 -- | Filter where the predicate returns a monadic `Boolean`.
 -- |
 -- | ```purescript