Added unflatten method.

benedict/dicts/__init__.py

@@ -157,6 +157,13 @@ class benedict(IODict, KeypathDict, ParseDict):
         """
         dict_util.traverse(self, callback)
 
+    def unflatten(self, separator='_'):
+        """
+        Return a new unflattened dict using the given separator
+        to split dict keys to nested keypaths.
+        """
+        return dict_util.unflatten(self, separator)
+
     def unique(self):
         """
         Remove duplicated values from the current dict instance.

benedict/utils/dict_util.py

@@ -214,6 +214,22 @@ def traverse(d, callback):
             traverse(value, callback)
 
 
+def unflatten(d, separator='_'):
+    new_dict = d.copy()
+    new_dict.clear()
+    new_dict_cursor = new_dict
+    keys = list(d.keys())
+    for key in keys:
+        value = d.get(key, None)
+        new_value = unflatten(value, separator=separator) if isinstance(
+            value, dict) else value
+        new_keys = key.split(separator) if separator in key else [key]
+        new_parent, new_key, _ = resolve(
+            new_dict, new_keys, create_intermediates=True)
+        new_parent[new_key] = new_value
+    return new_dict
+
+
 def unique(d):
     values = []
     keys = list(d.keys())

tests/test_benedict.py

@@ -1542,6 +1542,30 @@ b:
         }
         self.assertEqual(b, r)
 
+    def test_unflatten(self):
+        d = {
+            'device_os': 'Windows',
+            'device_lang': 'en-US',
+            'device_code': 43,
+            'browser_name': 'Chrome',
+            'browser_layout': 'Webkit',
+        }
+        b = benedict(d)
+        u = b.unflatten()
+        r = {
+            'device': {
+                'os': 'Windows',
+                'lang': 'en-US',
+                'code': 43,
+            },
+            'browser': {
+                'name': 'Chrome',
+                'layout': 'Webkit',
+            },
+        }
+        self.assertEqual(u, r)
+        self.assertEqual(u.flatten(), b)
+
     def test_unique(self):
         d = {
             'a': {