double在输出为字符串的几种方法效率测试

测试结果：

 

double->none 366ms
double->long 161ms
double->long2 188ms
double->format 564ms
double->Round 393ms

 

代码：

 

+ View Code?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95

using System; using System.Collections.Generic; using System.Diagnostics; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace testStringbuilder {     class Program     {         static void Main(string[] args)         {             const int count = 1000000;               RunTest("double->none",()=>             {                 StringBuilder sb = new StringBuilder(1000*1024*32);                 double a = 3.1415926;                 for (int i = 0; i < count; i++)                 {                     sb.Append(a);                     sb.Append(',');                 }             });               RunTest("double->long", () =>             {                 StringBuilder sb = new StringBuilder(1000 * 1024 * 32);                 double a = 3.1415926;                 for (int i = 0; i < count; i++)                 {                     sb.Append((long)a);                     sb.Append(',');                 }             });               RunTest("double->long2", () =>             {                 StringBuilder sb = new StringBuilder(1000 * 1024 * 32);                 double a = 3.1415926;                 for (int i = 0; i < count; i++)                 {                     sb.Append((long)(a * 100));                     sb.Append(',');                 }             });               RunTest("double->format", () =>             {                 StringBuilder sb = new StringBuilder(1000 * 1024 * 32);                 double a = 3.1415926;                 for (int i = 0; i < count; i++)                 {                     sb.AppendFormat("{0:f3}",a);                     sb.Append(',');                 }             });               RunTest("double->Round", () =>             {                 StringBuilder sb = new StringBuilder(1000 * 1024 * 32);                 double a = 3.1415926;                 for (int i = 0; i < count; i++)                 {                     sb.Append(Math.Round(a, 3));                     sb.Append(',');                 }             });         }           private static void RunTest(string key, Action action)         {             double milli = 0;             for (int i = 0; i < 3; i++)             {                 Stopwatch watch = Stopwatch.StartNew();                   try                 {                     action();                 }                 catch (Exception ex)                 {                     Console.WriteLine(ex);                 }                   watch.Stop();                 milli += watch.ElapsedMilliseconds;             }               Console.WriteLine("{0}\t{1}ms", key, (long) (milli/3));         }     } }