有没有比这样更快的方法?
private void EscapeStringSequence(ref string data)
{
data = data.Replace("\\", "\\\\"); // Backslash
data = data.Replace("\r", "\\r"); // Carriage return
data = data.Replace("\n", "\\n"); // New Line
data = data.Replace("\a", "\\a"); // Vertical tab
data = data.Replace("\b", "\\b"); // Backspace
data = data.Replace("\f", "\\f"); // Formfeed
data = data.Replace("\t", "\\t"); // Horizontal tab
data = data.Replace("\v", "\\v"); // Vertical tab
data = data.Replace("\"", "\\\""); // Double quotation mark
data = data.Replace("'", "\\'"); // Single quotation mark
}
-- 已编辑(添加说明) --
Q1:您是否有理由需要加快速度?会不会造成很大的问题?
这部分在这个项目中使用:http: //mysqlbackuprestore.codeplex.com/
我将重复循环大量不同长度的字符串到这个函数中。完成数百万行的整个过程大约需要 6-15 秒。还有其他部分也参与其中。我正在努力加快每个部分。
Q2:现在有多慢?
好的,我会记录所用的确切时间并在此处发布。我稍后再来。(明天会公布结果)
2012 年 6 月 29 日更新
我已经运行测试。结果如下:
速度测试:String.Replace() - 以毫秒为单位
测试 1:26749.7531 毫秒
测试 2:27063.438 毫秒
测试 3:27753.8884 毫秒
平均:27189.0265 毫秒
速度:100%
速度测试:Foreach Char 和追加- 以毫秒
测试 1:8468.4547 毫秒
测试 2:8348.8527 毫秒
测试 3:8353.6476 毫秒
平均:8390.3183 毫秒
速度:224% < 更快
======================== ===========
更新 - 下一次测试(另一轮)
=============================== ====
------
测试替换字符串速度。
测试 1:26535.6466
测试 2:26379.6464
测试 3:26379.6463
平均:26431.6464333333
速度:100%
------
测试 Foreach Char String Append。
测试 1:8502.015
测试 2:8517.6149
测试 3:8595.6151
平均:8538.415
速度:309.56%
------
测试 Foreach Char String Append(修复 StringBuilder 长度)。
测试 1:8314.8146
测试 2:8330.4147
测试 3:8346.0146
平均:8330.41463333333
速度:317.29%
结论:
使用 Foreach Char Loop 和 Append 比 String.Replace() 更快。
非常感谢你们。
--------
以下是我用来运行测试的代码:(已编辑)
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
Console.Write("Press any key to continue...");
Console.ReadKey();
Console.Write("\r\nProcess started.");
Test();
Console.WriteLine("Done.");
Console.Read();
}
public static Random random = new Random((int)DateTime.Now.Ticks);
public static string RandomString(int size)
{
StringBuilder sb = new StringBuilder();
char ch;
for (int i = 0; i < size; i++)
{
ch = Convert.ToChar(Convert.ToInt32(Math.Floor(26 * random.NextDouble() + 65)));
sb.Append(ch);
}
return sb.ToString();
}
public static void Test()
{
string text = "\\_\r\n\a\b\f\t\v\"'" + RandomString(2000) + "\\_\r\n\a\b\f\t\v\"'" + RandomString(2000);
List<TimeSpan> lstTimeUsed = new List<TimeSpan>();
int target = 100000;
for (int i = 0; i < 3; i++)
{
DateTime startTime = DateTime.Now;
for (int j = 0; j < target; j++)
{
if (j.ToString().EndsWith("000"))
{
Console.Clear();
Console.WriteLine("Test " + i.ToString());
Console.WriteLine(j.ToString() + " of " + target.ToString());
}
string data = text;
data = data.Replace("\\", "\\\\"); // Backslash
data = data.Replace("\r", "\\r"); // Carriage return
data = data.Replace("\n", "\\n"); // New Line
data = data.Replace("\a", "\\a"); // Vertical tab
data = data.Replace("\b", "\\b"); // Backspace
data = data.Replace("\f", "\\f"); // Formfeed
data = data.Replace("\t", "\\t"); // Horizontal tab
data = data.Replace("\v", "\\v"); // Vertical tab
data = data.Replace("\"", "\\\""); // Double quotation mark
data = data.Replace("'", "\\'"); // Single quotation mark
}
DateTime endTime = DateTime.Now;
TimeSpan ts = endTime - startTime;
lstTimeUsed.Add(ts);
}
double t1 = lstTimeUsed[0].TotalMilliseconds;
double t2 = lstTimeUsed[1].TotalMilliseconds;
double t3 = lstTimeUsed[2].TotalMilliseconds;
double tOri = (t1 + t2 + t3) / 3;
System.IO.TextWriter tw = new System.IO.StreamWriter("D:\\test.txt", true);
tw.WriteLine("------");
tw.WriteLine("Test Replace String Speed. Test Time: " + DateTime.Now.ToString());
tw.WriteLine("Test 1: " + t1.ToString());
tw.WriteLine("Test 2: " + t2.ToString());
tw.WriteLine("Test 3: " + t3.ToString());
tw.WriteLine("Average: " + tOri.ToString());
tw.WriteLine("Speed: 100%");
tw.Close();
lstTimeUsed = new List<TimeSpan>();
for (int i = 0; i < 3; i++)
{
DateTime startTime = DateTime.Now;
for (int j = 0; j < target; j++)
{
if (j.ToString().EndsWith("000"))
{
Console.Clear();
Console.WriteLine("Test " + i.ToString());
Console.WriteLine(j.ToString() + " of " + target.ToString());
}
string data = text;
var builder = new StringBuilder();
foreach (var ch in data)
{
switch (ch)
{
case '\\':
case '\r':
case '\n':
case '\a':
case '\b':
case '\f':
case '\t':
case '\v':
case '\"':
case '\'':
builder.Append('\\');
break;
default:
break;
}
builder.Append(ch);
}
}
DateTime endTime = DateTime.Now;
TimeSpan ts = endTime - startTime;
lstTimeUsed.Add(ts);
}
t1 = lstTimeUsed[0].TotalMilliseconds;
t2 = lstTimeUsed[1].TotalMilliseconds;
t3 = lstTimeUsed[2].TotalMilliseconds;
tw = new System.IO.StreamWriter("D:\\test.txt", true);
tw.WriteLine("------");
tw.WriteLine("Test Foreach Char String Append. Test Time: " + DateTime.Now.ToString());
tw.WriteLine("Test 1: " + t1.ToString());
tw.WriteLine("Test 2: " + t2.ToString());
tw.WriteLine("Test 3: " + t3.ToString());
tw.WriteLine("Average: " + ((t1 + t2 + t3) / 3).ToString());
tw.WriteLine("Speed: " + ((tOri) / ((t1 + t2 + t3) / 3) * 100).ToString("0.00") + "%");
tw.Close();
lstTimeUsed = new List<TimeSpan>();
for (int i = 0; i < 3; i++)
{
DateTime startTime = DateTime.Now;
for (int j = 0; j < target; j++)
{
if (j.ToString().EndsWith("000"))
{
Console.Clear();
Console.WriteLine("Test " + i.ToString());
Console.WriteLine(j.ToString() + " of " + target.ToString());
}
string data = text;
var builder = new StringBuilder(data.Length + 20);
foreach (var ch in data)
{
switch (ch)
{
case '\\':
case '\r':
case '\n':
case '\a':
case '\b':
case '\f':
case '\t':
case '\v':
case '\"':
case '\'':
builder.Append('\\');
break;
default:
break;
}
builder.Append(ch);
}
}
DateTime endTime = DateTime.Now;
TimeSpan ts = endTime - startTime;
lstTimeUsed.Add(ts);
}
t1 = lstTimeUsed[0].TotalMilliseconds;
t2 = lstTimeUsed[1].TotalMilliseconds;
t3 = lstTimeUsed[2].TotalMilliseconds;
tw = new System.IO.StreamWriter("D:\\test.txt", true);
tw.WriteLine("------");
tw.WriteLine("Test Foreach Char String Append (Fix StringBuilder Length). Test Time: " + DateTime.Now.ToString());
tw.WriteLine("Test 1: " + t1.ToString());
tw.WriteLine("Test 2: " + t2.ToString());
tw.WriteLine("Test 3: " + t3.ToString());
tw.WriteLine("Average: " + ((t1 + t2 + t3) / 3).ToString());
tw.WriteLine("Speed: " + ((tOri) / ((t1 + t2 + t3) / 3) * 100).ToString("0.00") + "%");
tw.Close();
}
}
}