1 static void Main(string[] args)
 2         {
 3             Stopwatch sw = new Stopwatch();
 4             Random rand=new Random();
 5             string output = "{0}运行使用了{1}毫秒";
 6
 7             List<int> intlist = new List<int>();
 8             const int length = 26843545;
 9             int temp;
10
11             for (int i = 0; i < length; i++)
12             {
13                 intlist.Add(i);
14             }
15
16             int target = rand.Next(length);
17
18             Console.WriteLine("总长度{0}，查找对象{1}", length, target);
19
20             List<int> forlist = new List<int>(); ;
21             forlist.Clear();
22             forlist.AddRange(intlist);
23
24             List<int> lambdalist = new List<int>();
25             lambdalist.Clear();
26             lambdalist.AddRange(intlist);
27
28             List<int> foreachlist = new List<int>();
29             foreachlist.Clear();
30             foreachlist.AddRange(intlist);
31
32             List<int> linqlist = new List<int>();
33             linqlist.Clear();
34             linqlist.AddRange(intlist);
35             //------------------------------------
36             // for
37             sw.Reset();
38             sw.Start();
39             for (int i = 0; i < length; i++)
40             {
41                 if (forlist[i]==target)
42                 {
43                     temp = forlist[i];
44                     sw.Stop();
45                     Console.WriteLine(output, "for循环",sw.ElapsedMilliseconds);
46                 }
47             }
48             //----------------------------------------------------------
49             //foreach
50             sw.Reset();
51             sw.Start();
52             foreach (int item in foreachlist)
53             {
54                 if (item == target)
55                 {
56                     temp = item;
57                     sw.Stop();
58                     Console.WriteLine(output, "foreach循环", sw.ElapsedMilliseconds);
59                 }
60             }
61             //------------------------------------------------
62             //lambda
63             sw.Reset();
64             sw.Start();
65            temp= lambdalist.Where(x => x == target).First();
66             sw.Stop();
67             Console.WriteLine(output, "Lambda表达式", sw.ElapsedMilliseconds);
68             //----------------------------------------------------
69             //Linq
70             sw.Reset();
71             sw.Start();
72             temp = (from y in linqlist
73                     where y == target
74                     select y).First();
75             sw.Stop();
76             Console.WriteLine(output, "Linq查询", sw.ElapsedMilliseconds);
77             //-----------------------------------------------------------
78             Console.Read();
79         }

 1 private static Func<TSource, bool> CombinePredicates<TSource>(Func<TSource, bool> predicate1, Func<TSource, bool> predicate2)
 2 {
 3     return delegate (TSource x) {
 4         if (predicate1(x))
 5         {
 6             return predicate2(x);
 7         }
 8         return false;
 9     };
10 }
11
12
13
14