相关疑难解决方法(0)

我很惊讶,无论我是在前置还是附加LINQ扩展方法都没关系.

经测试Enumerable.FirstOrDefault:

1. hugeList.Where(x => x.Text.Contains("10000")).FirstOrDefault();

2. hugeList.FirstOrDefault(x => x.Text.Contains("10000"));

   var hugeList = Enumerable.Range(1, 50000000)
       .Select(i => new { ID = i, Text = "Item" + i });
   
   var sw1 = new System.Diagnostics.Stopwatch();
   var sw2 = new System.Diagnostics.Stopwatch();
   
   sw1.Start();
   for(int i=0;i<1000;i++)
       hugeList.Where(x => x.Text.Contains("10000")).FirstOrDefault();
   sw1.Stop();
   
   sw2.Start();
   for(int i=0;i<1000;i++)
       hugeList.FirstOrDefault(x => x.Text.Contains("10000"));
   sw2.Stop();
   
   var result1 = String.Format("FirstOrDefault after: {0} FirstOrDefault before: {1}", sw1.Elapsed,  sw2.Elapsed);
   //result1: FirstOrDefault after: 00:00:03.3169683 FirstOrDefault before: 00:00:03.0463219
   
   sw2.Restart();
   for (int i = 0; i < 1000; i++) …

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