为什么StringBuilder与连接相比较慢?
StringBuilder旨在避免额外的对象创建,但是为什么会影响性能?
StringBuilder旨在避免额外的对象创建,但是为什么会影响性能?
static void Main(string[] args) { int max = 1000000; for (int times = 0; times < 5; times++) { Console.WriteLine("\ntime: {0}",(times+1).ToString()); Stopwatch sw = Stopwatch.StartNew(); for (int i = 0; i < max; i++) { string msg = "Your total is "; msg += "$500 "; msg += DateTime.Now; } sw.Stop(); Console.WriteLine("String +\t: {0}ms",((int)sw.ElapsedMilliseconds).ToString().PadLeft(6)); sw = Stopwatch.StartNew(); for (int j = 0; j < max; j++) { StringBuilder msg = new StringBuilder(); msg.Append("Your total is "); msg.Append("$500 "); msg.Append(DateTime.Now); } sw.Stop(); Console.WriteLine("StringBuilder\t: {0}ms",((int)sw.ElapsedMilliseconds).ToString().PadLeft(6)); } Console.Read(); }
编辑:根据建议移出范围变量:
解决方法
更改,以使StringBuilder不被实例化,而不是.Clear()它:
time: 1 String + : 3348ms StringBuilder : 3151ms time: 2 String + : 3346ms StringBuilder : 3050ms
等等
请注意,这仍然测试完全相同的功能,但尝试重新使用资源一点更聪明.
代码:(也住在http://ideone.com/YuaqY)
using System; using System.Text; using System.Diagnostics; public class Program { static void Main(string[] args) { int max = 1000000; for (int times = 0; times < 5; times++) { { Console.WriteLine("\ntime: {0}",(times+1).ToString()); Stopwatch sw = Stopwatch.StartNew(); for (int i = 0; i < max; i++) { string msg = "Your total is "; msg += "$500 "; msg += DateTime.Now; } sw.Stop(); Console.WriteLine("String +\t: {0}ms",((int)sw.ElapsedMilliseconds).ToString().PadLeft(6)); } { Stopwatch sw = Stopwatch.StartNew(); StringBuilder msg = new StringBuilder(); for (int j = 0; j < max; j++) { msg.Clear(); msg.Append("Your total is "); msg.Append("$500 "); msg.Append(DateTime.Now); } sw.Stop(); Console.WriteLine("StringBuilder\t: {0}ms",((int)sw.ElapsedMilliseconds).ToString().PadLeft(6)); } } Console.Read(); } }
原文地址:https://www.jb51.cc/csharp/93919.html
版权声明:本文内容由互联网用户自发贡献,该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务,不拥有所有权,不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容, 请发送邮件至 dio@foxmail.com 举报,一经查实,本站将立刻删除。