继续测试-查找一定范围内的自定义对象集合

这次换了一个自定义的对象Student。然后根据成绩（Mark字段，取值范围0-99）范围查找符合条件的学生，重新用一个list装起来。

上代码。

全部代码 
  1 class Student
  2     {
  3         public int SID { get; set; }
  4         public string SName { get; set; }
  5         public int Mark { get; set; }
  6 
  7     }
  8     class Program
  9     {
 10         static void Main(string[] args)
 11         {
 12             Stopwatch sw = new Stopwatch();
 13             Random rand=new Random();
 14             string output = "{0}运行使用了{1}毫秒";
 15 
 16             List<Student> intlist = new List<Student>();
 17             const int length = 14843545;
 18             List<Student> temp=new List<Student>();
 19            
 20 
 21             for (int i = 0; i < length; i++)
 22             {
 23                 intlist.Add(new Student
 24                 {
 25                     SID=i,
 26                     SName=i.ToString(),
 27                     Mark=rand.Next(100)
 28                 });
 29             }
 30 
 31             int high = rand.Next(100);
 32             int low = rand.Next(high);
 33             int mark;
 34 
 35             Console.WriteLine("总元素个数{0}，查找范围{1}-{2}", length,low, high);
 36 
 37             List<Student> forlist = new List<Student>(); ;
 38             forlist.Clear();
 39             forlist.AddRange(intlist);
 40 
 41             List<Student> lambdalist = new List<Student>();
 42             lambdalist.Clear();
 43             lambdalist.AddRange(intlist);
 44 
 45             List<Student> foreachlist = new List<Student>();
 46             foreachlist.Clear();
 47             foreachlist.AddRange(intlist);
 48 
 49             List<Student> linqlist = new List<Student>();
 50             linqlist.Clear();
 51             linqlist.AddRange(intlist);
 52             //------------------------------------
 53             // for
 54             sw.Reset();
 55             temp.Clear();
 56             sw.Start();
 57             
 58             for (int i = 0; i < length; i++)
 59             {
 60                 mark = forlist[i].Mark;
 61                 if (mark <= high && mark >= low)
 62                 {
 63                     temp.Add(forlist[i]);                    
 64                 }                
 65             }
 66             sw.Stop();
 67             Console.WriteLine("满足条件的元素有{0}个",temp.Count);
 68             Console.WriteLine(output, "for循环", sw.ElapsedMilliseconds);
 69             //----------------------------------------------------------
 70             //foreach
 71             sw.Reset();
 72             temp.Clear();
 73             sw.Start();
 74             
 75             foreach (Student item in foreachlist)
 76             {
 77                 mark = item.Mark;
 78                 if (mark <= high && mark >= low)
 79                 {
 80                     temp.Add(item);                    
 81                 }
 82             }
 83             sw.Stop();
 84             Console.WriteLine(output, "foreach循环", sw.ElapsedMilliseconds);
 85             //------------------------------------------------
 86             //lambda
 87             sw.Reset();
 88             temp.Clear();
 89             sw.Start();
 90            temp= lambdalist.Where(x => x.Mark <= high&& x.Mark>=low).ToList();
 91             
 92             sw.Stop();
 93             Console.WriteLine(output, "Lambda表达式", sw.ElapsedMilliseconds);
 94             //----------------------------------------------------
 95             //Linq
 96            
 97             sw.Reset();
 98             temp.Clear();
 99             sw.Start();
100             temp = (from y in linqlist
101                     where y.Mark<= high && y.Mark>=low
102                     select y).ToList();  
103             sw.Stop();
104             Console.WriteLine(output, "Linq查询", sw.ElapsedMilliseconds);
105             //-----------------------------------------------------------
106             Console.Read();
107         }
108     }

 

测试结果：

范围 符合个数 for foreach Lambda Linq
29-68 5938385 542 535 692 715
21-70 7422882 426 651 972 689
14-35 3265893 606 380 812 493
24-46 3414418 274 336 547 556
87-92 891347 199 235 347 340
19-29 1632824 214 274 407 416
32-33 296897 188 264 363 369
3-11 1335090 193 234 363 395
4-7 593746 216 279 430 619
0-6 1039583 173 208 319 323
4-33 4451722 396 380 860 562
12-76 9647771 433 380 4426 674
10-75 9793927 379 361 3961 651
57-99 6384332 306 324 634 640

这次就有点怪异了。在结果的数据量级比较大时，foreach有几次比for还快。lambda与linq谁也没占多少便宜。达到几秒那几次lambda的时间可能刚好碰上GC了，所以不能作为参考。

posted @ 2012-07-31 14:47  BonizLee  阅读(190)  评论(0)  编辑  收藏  举报