Core/Refactor: Part 3

Source/Framework/Util/CollectionExtensions.cs

@@ -66,6 +66,9 @@ namespace System.Collections.Generic
         }
         public static KeyValuePair<TKey, TValue> Find<TKey, TValue>(this IDictionary<TKey, TValue> dict, TKey key)
         {
+            if (!dict.ContainsKey(key))
+                return default(KeyValuePair<TKey, TValue>);
+
             return new KeyValuePair<TKey, TValue>(key, dict[key]);
         }
 
@@ -113,17 +116,17 @@ namespace System.Collections.Generic
             }
         }
 
-        public static void RandomResize<T>(this ICollection<T> list, Predicate<T> predicate, uint size)
+        public static void RandomResize<T>(this List<T> list, Predicate<T> predicate, uint size)
         {
-            List<T> listCopy = new List<T>();
-            foreach (var obj in list)
-                if (predicate(obj))
-                    listCopy.Add(obj);
+            for (var i = 0; i < list.Count; ++i)
+            {
+                var obj = list[i];
+                if (!predicate(obj))
+                    list.Remove(obj);
+            }
 
             if (size != 0)
-                listCopy.Resize(size);
-
-            list = listCopy;
+                list.Resize(size);
         }
 
         public static T SelectRandom<T>(this IEnumerable<T> source)