是否有比做這樣更快任何其他方法?比快與string.replace()
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
}
- 編輯(添加說明) -
Q1:是否有你爲什麼需要加快它的理由?這是造成一個巨大的問題嗎?
這個部分用於這個項目:http://mysqlbackuprestore.codeplex.com/
我要循環大量不同長度的字符串到這個函數重複。整個過程需要大約6-15秒才能完成數百萬行。還有其他部分也涉及到。我試圖加快每一個部分。
Q2:如何慢,現在是什麼呢?
OK,我會捕捉使用的確切時間,並張貼在這裏。我以後會回來的。 (會後的結果明天)
更新29-06-2012
嘿,夥計們。我已經運行測試。這是結果:
速度測試:與string.replace() - 以毫秒爲單位測量
測試1:26749.7531毫秒
試驗2:27063.438毫秒
試驗3:27753.8884毫秒
平均:27189.0265毫秒
速度:100%
速度測試:FOREACH Char和追加 - 以毫秒爲單位
試驗1測得:8468.4547毫秒
試驗2:8348.8527毫秒
試驗3:8353.6476毫秒
平均:8390.3183毫秒
速度:224%<更快
================== =================
更新 - 下一個測試(另一輪)
=================== ================
------
測試替換字符串速度。
測試1:26535.6466
試驗2:26379.6464
試驗3:26379.6463
平均:26431.6464333333
速度:100%
------
測試FOREACH字符字符串追加。
測試1:8502.015
試驗2:8517.6149
試驗3:8595.6151
平均:8538.415
速度:309.56%
------
測試FOREACH字符字符串附加(修正StringBuilder的長度)。
測試1:8314.8146
試驗2:8330。4147
測試3:8346.0146
平均:8330.41463333333
速度:317.29%
結論:
使用的foreach循環炭和追加比速度與string.replace()。
非常感謝你的傢伙。
--------
下面是我用來運行測試代碼:(編輯)
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();
}
}
}
如何慢,現在是什麼呢?的 –
可能重複的[最快的方式在模板替換字符串](http://stackoverflow.com/questions/959940/fastest-way-to-replace-string-in-a-template) – adatapost
把字符串轉換成一個StringBuilder然後使用StringBuilder.Replace可能會更快。編寫自己的構建結果字符串的單遍循環應該快得多。 – hatchet