update

Packages/Runtime~/Core/Mathematics/MathE.cs

@@ -60,6 +60,7 @@ namespace BITKit
 
             return true;
         }
+
         public static IEnumerable<T[]> Combinations<T>(IEnumerable<T> source)
         {
             if (null == source) throw new ArgumentNullException(nameof(source));
@@ -74,13 +75,14 @@ namespace BITKit
             switch (self)
             {
                 case List<T> list:
-                    list.Insert(index,item);
+                    list.Insert(index, item);
                     break;
                 default:
                     var _list = self.ToList();
-                    _list.Insert(index,item);
+                    _list.Insert(index, item);
                     return _list;
             }
+
             return self;
         }
 
@@ -91,8 +93,10 @@ namespace BITKit
             {
                 value = self.ElementAt(0);
             }
+
             return value is not null;
         }
+
         /// <summary>
         /// 组合集合中的所有元素
         /// </summary>
@@ -113,6 +117,7 @@ namespace BITKit
                 }
             }
         }
+
         /// <summary>
         /// 获取集合中所有的组合,每个组合中的元素个数为输入集合的元素个数,每个元素只出现一次
         /// </summary>
@@ -132,5 +137,34 @@ namespace BITKit
                 }
             }
         }
+        /// <summary>
+        /// Linq Distinct扩展方法,可以传入自定义比较器
+        /// </summary>
+        /// <param name="source"></param>
+        /// <param name="comparer"></param>
+        /// <typeparam name="T"></typeparam>
+        /// <returns></returns>
+        public static IEnumerable<T> Distinct<T>(
+            this IEnumerable<T> source, Func<T, T, bool> comparer)
+            where T : class
+            => source.Distinct(new DynamicEqualityComparer<T>(comparer));
+        /// <summary>
+        /// 动态自定义比较器
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        private sealed class DynamicEqualityComparer<T> : IEqualityComparer<T>
+            where T : class
+        {
+            private readonly Func<T, T, bool> _func;
+
+            public DynamicEqualityComparer(Func<T, T, bool> func)
+            {
+                _func = func;
+            }
+
+            public bool Equals(T x, T y) => _func(x, y);
+
+            public int GetHashCode(T obj) => 0;
+        }
     }
 }