印象里面Length会统计字符串长度会比较慢！但是没想到是Length比较块！丢脸了！ #region --空字符串判断最快测试-- /// <summary> /// 空字符串判断最快测试 /// </summary> public class FastCheckEmptyString { /// <summary> /// 空字符串判断最快测试 /// </summary> public static void Run() { StringBuilder sb = new StringBuilder(); for (int i = 0; i < 20000; i++) { sb.Append("ABCDEFGHIJKLMNOPQRSTUVWXYZ"); } string str = sb.ToString(); System.Diagnostics.Stopwatch st = new System.Diagnostics.Stopwatch(); st.Start(); for (int i = 0; i < 100000000; i++) { if (str == "") { } } st.Stop(); Console.WriteLine("str == '' : " + st.ElapsedMilliseconds); st.Restart(); //st.Start(); for (int i = 0; i < 100000000; i++) { if (str == String.Empty) { } } st.Stop(); Console.WriteLine("str == String.Empty : " + st.ElapsedMilliseconds); //st = new System.Diagnostics.Stopwatch(); st.Restart(); //st.Start(); for (int i = 0; i < 100000000; i++) { if (str.Length == 0) { } } st.Stop(); Console.WriteLine("str.Length == 0 : " + st.ElapsedMilliseconds); st.Restart(); //st.Start(); for (int i = 0; i < 100000000; i++) { if (!string.IsNullOrEmpty(str)) { } } st.Stop(); Console.WriteLine("!string.IsNullOrEmpty(str) : " + st.ElapsedMilliseconds); //end } } #endregion
测试结果采样：
str == '' : 495
str == String.Empty : 413
str.Length == 0 : 343
!string.IsNullOrEmpty(str) : 317
IsNullOrEmpty() 王者！，其次是Length，其他两种都稍差！
话说回来！还是优化 结构 和 其他缓慢点，优化算法才是王道! 优化这个 性价比不高！