感谢大家的输入。我编写了一个快速而简单的基准测试来测试你们的输入。我已经测试了解析4个字符串,进行了500,000次迭代,并完成了4次传递。结果如下:
*** Pass 1
使用旧的(链式字符串替换)方法完成时间为814毫秒
logicnp (ToCharArray)方法完成时间为916毫秒
oleksii (StringBuilder)方法完成时间为943毫秒
André Christoffer Andersen (Lambda w/ Aggregate)方法完成时间为2551毫秒
Richard (Regex w/ MatchEvaluator)方法完成时间为215毫秒
Marc Gravell (Static Regex)方法完成时间为1008毫秒
*** Pass 2
使用旧的(链式字符串替换)方法完成时间为786毫秒
logicnp (ToCharArray)方法完成时间为920毫秒
oleksii (StringBuilder)方法完成时间为905毫秒
André Christoffer Andersen (Lambda w/ Aggregate)方法完成时间为2515毫秒
Richard (Regex w/ MatchEvaluator)方法完成时间为217毫秒
Marc Gravell (Static Regex)方法完成时间为1025毫秒
*** Pass 3
使用旧的(链式字符串替换)方法完成时间为775毫秒
logicnp (ToCharArray)方法完成时间为903毫秒
oleksii (StringBuilder)方法完成时间为931毫秒
André Christoffer Andersen (Lambda w/ Aggregate)方法完成时间为2529毫秒
Richard (Regex w/ MatchEvaluator)方法完成时间为214毫秒
Marc Gravell (Static Regex)方法完成时间为1022毫秒
*** Pass 4
使用旧的(链式字符串替换)方法完成时间为799毫秒
logicnp (ToCharArray)方法完成时间为908毫秒
oleksii (StringBuilder)方法完成时间为938毫秒
André Christoffer Andersen (Lambda w/ Aggregate)方法完成时间为2592毫秒
Richard (Regex w/ MatchEvaluator)方法完成时间为225毫秒
Marc Gravell (Static Regex)方法完成时间为1050毫秒
以下是此基准测试的代码。请查看代码并确认@Richard拥有最快的方法。请注意,我没有检查输出是否正确,我认为它们是正确的。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.Text.RegularExpressions;
namespace StringReplaceTest
{
class Program
{
static string test1 = "A^@[BCD";
static string test2 = "E]FGH\\";
static string test3 = "ijk`l}m";
static string test4 = "nopq~{r";
static readonly Dictionary<char, string> repl =
new Dictionary<char, string>
{
{'^', "Č"}, {'@', "Ž"}, {'[', "Š"}, {']', "Ć"}, {'`', "ž"}, {'}', "ć"}, {'~', "č"}, {'{', "š"}, {'\\', "Đ"}
};
static readonly Regex replaceRegex;
static Program()
{
StringBuilder pattern = new StringBuilder().Append('[');
foreach (var key in repl.Keys)
pattern.Append(Regex.Escape(key.ToString()));
pattern.Append(']');
replaceRegex = new Regex(pattern.ToString(), RegexOptions.Compiled);
}
public static string Sanitize(string input)
{
return replaceRegex.Replace(input, match =>
{
return repl[match.Value[0]];
});
}
static string DoGeneralReplace(string input)
{
var sb = new StringBuilder(input);
return sb.Replace('^', 'Č').Replace('@', 'Ž').Replace('[', 'Š').Replace(']', 'Ć').Replace('`', 'ž').Replace('}', 'ć').Replace('~', 'č').Replace('{', 'š').Replace('\\', 'Đ').ToString();
}
static string Replace(string input, IDictionary<char, char> replacementMap)
{
return replacementMap.Keys
.Aggregate(input, (current, oldChar)
=> current.Replace(oldChar, replacementMap[oldChar]));
}
static void Main(string[] args)
{
for (int i = 1; i < 5; i++)
DoIt(i);
}
static void DoIt(int n)
{
Stopwatch sw = new Stopwatch();
int idx = 0;
Console.WriteLine("*** Pass " + n.ToString());
sw.Start();
for (idx = 0; idx < 500000; idx++)
{
string result1 = test1.Replace('^', 'Č').Replace('@', 'Ž').Replace('[', 'Š').Replace(']', 'Ć').Replace('`', 'ž').Replace('}', 'ć').Replace('~', 'č').Replace('{', 'š').Replace('\\', 'Đ');
string result2 = test2.Replace('^', 'Č').Replace('@', 'Ž').Replace('[', 'Š').Replace(']', 'Ć').Replace('`', 'ž').Replace('}', 'ć').Replace('~', 'č').Replace('{', 'š').Replace('\\', 'Đ');
string result3 = test3.Replace('^', 'Č').Replace('@', 'Ž').Replace('[', 'Š').Replace(']', 'Ć').Replace('`', 'ž').Replace('}', 'ć').Replace('~', 'č').Replace('{', 'š').Replace('\\', 'Đ');
string result4 = test4.Replace('^', 'Č').Replace('@', 'Ž').Replace('[', 'Š').Replace(']', 'Ć').Replace('`', 'ž').Replace('}', 'ć').Replace('~', 'č').Replace('{', 'š').Replace('\\', 'Đ');
}
sw.Stop();
Console.WriteLine("Old (Chained String.Replace()) way completed in " + sw.ElapsedMilliseconds.ToString() + " ms");
Dictionary<char, char> replacements = new Dictionary<char, char>();
replacements.Add('^', 'Č');
replacements.Add('@', 'Ž');
replacements.Add('[', 'Š');
replacements.Add(']', 'Ć');
replacements.Add('`', 'ž');
replacements.Add('}', 'ć');
replacements.Add('~', 'č');
replacements.Add('{', 'š');
replacements.Add('\\', 'Đ');
sw.Reset();
sw.Start();
for (idx = 0; idx < 500000; idx++)
{
char[] charArray1 = test1.ToCharArray();
for (int i = 0; i < charArray1.Length; i++)
{
char newChar;
if (replacements.TryGetValue(test1[i], out newChar))
charArray1[i] = newChar;
}
string result1 = new string(charArray1);
char[] charArray2 = test2.ToCharArray();
for (int i = 0; i < charArray2.Length; i++)
{
char newChar;
if (replacements.TryGetValue(test2[i], out newChar))
charArray2[i] = newChar;
}
string result2 = new string(charArray2);
char[] charArray3 = test3.ToCharArray();
for (int i = 0; i < charArray3.Length; i++)
{
char newChar;
if (replacements.TryGetValue(test3[i], out newChar))
charArray3[i] = newChar;
}
string result3 = new string(charArray3);
char[] charArray4 = test4.ToCharArray();
for (int i = 0; i < charArray4.Length; i++)
{
char newChar;
if (replacements.TryGetValue(test4[i], out newChar))
charArray4[i] = newChar;
}
string result4 = new string(charArray4);
}
sw.Stop();
Console.WriteLine("logicnp (ToCharArray) way completed in " + sw.ElapsedMilliseconds.ToString() + " ms");
sw.Reset();
sw.Start();
for (idx = 0; idx < 500000; idx++)
{
string result1 = DoGeneralReplace(test1);
string result2 = DoGeneralReplace(test2);
string result3 = DoGeneralReplace(test3);
string result4 = DoGeneralReplace(test4);
}
sw.Stop();
Console.WriteLine("oleksii (StringBuilder) way completed in " + sw.ElapsedMilliseconds.ToString() + " ms");
sw.Reset();
sw.Start();
for (idx = 0; idx < 500000; idx++)
{
string result1 = Replace(test1, replacements);
string result2 = Replace(test2, replacements);
string result3 = Replace(test3, replacements);
string result4 = Replace(test4, replacements);
}
sw.Stop();
Console.WriteLine("André Christoffer Andersen (Lambda w/ Aggregate) way completed in " + sw.ElapsedMilliseconds.ToString() + " ms");
sw.Reset();
sw.Start();
Regex reg = new Regex(@"\^|@|\[|\]|`|\}|~|\{|\\");
MatchEvaluator eval = match =>
{
switch (match.Value)
{
case "^": return "Č";
case "@": return "Ž";
case "[": return "Š";
case "]": return "Ć";
case "`": return "ž";
case "}": return "ć";
case "~": return "č";
case "{": return "š";
case "\\": return "Đ";
default: throw new Exception("Unexpected match!");
}
};
for (idx = 0; idx < 500000; idx++)
{
string result1 = reg.Replace(test1, eval);
string result2 = reg.Replace(test2, eval);
string result3 = reg.Replace(test3, eval);
string result4 = reg.Replace(test4, eval);
}
sw.Stop();
Console.WriteLine("Richard (Regex w/ MatchEvaluator) way completed in " + sw.ElapsedMilliseconds.ToString() + " ms");
sw.Reset();
sw.Start();
for (idx = 0; idx < 500000; idx++)
{
string result1 = Sanitize(test1);
string result2 = Sanitize(test2);
string result3 = Sanitize(test3);
string result4 = Sanitize(test4);
}
sw.Stop();
Console.WriteLine("Marc Gravell (Static Regex) way completed in " + sw.ElapsedMilliseconds.ToString() + " ms\n");
}
}
}
2020年6月更新
由于这个问题仍然受到关注,我想添加来自user1664043的额外输入,使用StringBuilder w/ IndexOfAny编译了.NET Core 3.1,以下是结果:
*** 第一次测试
旧方法(串联String.Replace())完成时间为199毫秒
logicnp(ToCharArray)方式完成时间为296毫秒
oleksii(StringBuilder)方式完成时间为416毫秒
André Christoffer Andersen(Lambda w/ Aggregate)方式完成时间为870毫秒
Richard(Regex w/ MatchEvaluator)方式完成时间为1722毫秒
Marc Gravell(Static Regex)方式完成时间为395毫秒
user1664043(StringBuilder w/ IndexOfAny)方式完成时间为459毫秒
*** 第二次测试
旧方法(串联String.Replace())完成时间为215毫秒
logicnp(ToCharArray)方式完成时间为239毫秒
oleksii(StringBuilder)方式完成时间为341毫秒
André Christoffer Andersen(Lambda w/ Aggregate)方式完成时间为758毫秒
Richard(Regex w/ MatchEvaluator)方式完成时间为1591毫秒
Marc Gravell(Static Regex)方式完成时间为354毫秒
user1664043(StringBuilder w/ IndexOfAny)方式完成时间为426毫秒
*** 第三次测试
旧方法(串联String.Replace())完成时间为199毫秒
logicnp(ToCharArray)方式完成时间为265毫秒
oleksii(StringBuilder)方式完成时间为337毫秒
André Christoffer Andersen(Lambda w/ Aggregate)方式完成时间为817毫秒
Richard(Regex w/ MatchEvaluator)方式完成时间为1666毫秒
Marc Gravell(Static Regex)方式完成时间为373毫秒
user1664043(StringBuilder w/ IndexOfAny)方式完成时间为412毫秒
*** 第四次测试
旧方法(串联String.Replace())完成时间为199毫秒
logicnp(ToCharArray)方式完成时间为230毫秒
oleksii(StringBuilder)方式完成时间为324毫秒
André Christoffer Andersen(Lambda w/ Aggregate)方式完成时间为791毫秒
Richard(Regex w/ MatchEvaluator)方式完成时间为1699毫秒
Marc Gravell(Static Regex)方式完成时间为359毫秒
user1664043(StringBuilder w/ IndexOfAny)方式完成时间为413毫秒
更新后的代码:
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
namespace Test.StringReplace
{
class Program
{
static string test1 = "A^@[BCD";
static string test2 = "E]FGH\\";
static string test3 = "ijk`l}m";
static string test4 = "nopq~{r";
static readonly Dictionary<char, string> repl =
new Dictionary<char, string>
{
{'^', "Č"}, {'@', "Ž"}, {'[', "Š"}, {']', "Ć"}, {'`', "ž"}, {'}', "ć"}, {'~', "č"}, {'{', "š"}, {'\\', "Đ"}
};
static readonly Regex replaceRegex;
static readonly char[] badChars = new char[] { '^', '@', '[', ']', '`', '}', '~', '{', '\\' };
static readonly char[] replacementChars = new char[] { 'Č', 'Ž', 'Š', 'Ć', 'ž', 'ć', 'č', 'š', 'Đ' };
static Program()
{
StringBuilder pattern = new StringBuilder().Append('[');
foreach (var key in repl.Keys)
pattern.Append(Regex.Escape(key.ToString()));
pattern.Append(']');
replaceRegex = new Regex(pattern.ToString(), RegexOptions.Compiled);
}
public static string Sanitize(string input)
{
return replaceRegex.Replace(input, match =>
{
return repl[match.Value[0]];
});
}
static string DoGeneralReplace(string input)
{
var sb = new StringBuilder(input);
return sb.Replace('^', 'Č').Replace('@', 'Ž').Replace('[', 'Š').Replace(']', 'Ć').Replace('`', 'ž').Replace('}', 'ć').Replace('~', 'č').Replace('{', 'š').Replace('\\', 'Đ').ToString();
}
static string Replace(string input, IDictionary<char, char> replacementMap)
{
return replacementMap.Keys
.Aggregate(input, (current, oldChar)
=> current.Replace(oldChar, replacementMap[oldChar]));
}
static string ReplaceCharsWithIndexOfAny(string sIn)
{
int replChar = sIn.IndexOfAny(badChars);
if (replChar < 0)
return sIn;
StringBuilder sb = new StringBuilder(sIn, 0, replChar, sIn.Length + 10);
while (replChar >= 0 && replChar < sIn.Length)
{
var c = replacementChars[replChar];
sb.Append(c);
replChar++;
if (replChar < sIn.Length)
{
int nextRepChar = sIn.IndexOfAny(badChars, replChar);
sb.Append(sIn, replChar, (nextRepChar > 0 ? nextRepChar : sIn.Length) - replChar);
replChar = nextRepChar;
}
}
return sb.ToString();
}
static void Main(string[] args)
{
for (int i = 1; i < 5; i++)
DoIt(i);
}
static void DoIt(int n)
{
Stopwatch sw = new Stopwatch();
int idx = 0;
Console.WriteLine("*** Pass " + n.ToString());
sw.Start();
for (idx = 0; idx < 500000; idx++)
{
string result1 = test1.Replace('^', 'Č').Replace('@', 'Ž').Replace('[', 'Š').Replace(']', 'Ć').Replace('`', 'ž').Replace('}', 'ć').Replace('~', 'č').Replace('{', 'š').Replace('\\', 'Đ');
string result2 = test2.Replace('^', 'Č').Replace('@', 'Ž').Replace('[', 'Š').Replace(']', 'Ć').Replace('`', 'ž').Replace('}', 'ć').Replace('~', 'č').Replace('{', 'š').Replace('\\', 'Đ');
string result3 = test3.Replace('^', 'Č').Replace('@', 'Ž').Replace('[', 'Š').Replace(']', 'Ć').Replace('`', 'ž').Replace('}', 'ć').Replace('~', 'č').Replace('{', 'š').Replace('\\', 'Đ');
string result4 = test4.Replace('^', 'Č').Replace('@', 'Ž').Replace('[', 'Š').Replace(']', 'Ć').Replace('`', 'ž').Replace('}', 'ć').Replace('~', 'č').Replace('{', 'š').Replace('\\', 'Đ');
}
sw.Stop();
Console.WriteLine("Old (Chained String.Replace()) way completed in " + sw.ElapsedMilliseconds.ToString() + " ms");
Dictionary<char, char> replacements = new Dictionary<char, char>();
replacements.Add('^', 'Č');
replacements.Add('@', 'Ž');
replacements.Add('[', 'Š');
replacements.Add(']', 'Ć');
replacements.Add('`', 'ž');
replacements.Add('}', 'ć');
replacements.Add('~', 'č');
replacements.Add('{', 'š');
replacements.Add('\\', 'Đ');
sw.Reset();
sw.Start();
for (idx = 0; idx < 500000; idx++)
{
char[] charArray1 = test1.ToCharArray();
for (int i = 0; i < charArray1.Length; i++)
{
char newChar;
if (replacements.TryGetValue(test1[i], out newChar))
charArray1[i] = newChar;
}
string result1 = new string(charArray1);
char[] charArray2 = test2.ToCharArray();
for (int i = 0; i < charArray2.Length; i++)
{
char newChar;
if (replacements.TryGetValue(test2[i], out newChar))
charArray2[i] = newChar;
}
string result2 = new string(charArray2);
char[] charArray3 = test3.ToCharArray();
for (int i = 0; i < charArray3.Length; i++)
{
char newChar;
if (replacements.TryGetValue(test3[i], out newChar))
charArray3[i] = newChar;
}
string result3 = new string(charArray3);
char[] charArray4 = test4.ToCharArray();
for (int i = 0; i < charArray4.Length; i++)
{
char newChar;
if (replacements.TryGetValue(test4[i], out newChar))
charArray4[i] = newChar;
}
string result4 = new string(charArray4);
}
sw.Stop();
Console.WriteLine("logicnp (ToCharArray) way completed in " + sw.ElapsedMilliseconds.ToString() + " ms");
sw.Reset();
sw.Start();
for (idx = 0; idx < 500000; idx++)
{
string result1 = DoGeneralReplace(test1);
string result2 = DoGeneralReplace(test2);
string result3 = DoGeneralReplace(test3);
string result4 = DoGeneralReplace(test4);
}
sw.Stop();
Console.WriteLine("oleksii (StringBuilder) way completed in " + sw.ElapsedMilliseconds.ToString() + " ms");
sw.Reset();
sw.Start();
for (idx = 0; idx < 500000; idx++)
{
string result1 = Replace(test1, replacements);
string result2 = Replace(test2, replacements);
string result3 = Replace(test3, replacements);
string result4 = Replace(test4, replacements);
}
sw.Stop();
Console.WriteLine("André Christoffer Andersen (Lambda w/ Aggregate) way completed in " + sw.ElapsedMilliseconds.ToString() + " ms");
sw.Reset();
sw.Start();
Regex reg = new Regex(@"\^|@|\[|\]|`|\}|~|\{|\\");
MatchEvaluator eval = match =>
{
switch (match.Value)
{
case "^": return "Č";
case "@": return "Ž";
case "[": return "Š";
case "]": return "Ć";
case "`": return "ž";
case "}": return "ć";
case "~": return "č";
case "{": return "š";
case "\\": return "Đ";
default: throw new Exception("Unexpected match!");
}
};
for (idx = 0; idx < 500000; idx++)
{
string result1 = reg.Replace(test1, eval);
string result2 = reg.Replace(test2, eval);
string result3 = reg.Replace(test3, eval);
string result4 = reg.Replace(test4, eval);
}
sw.Stop();
Console.WriteLine("Richard (Regex w/ MatchEvaluator) way completed in " + sw.ElapsedMilliseconds.ToString() + " ms");
sw.Reset();
sw.Start();
for (idx = 0; idx < 500000; idx++)
{
string result1 = Sanitize(test1);
string result2 = Sanitize(test2);
string result3 = Sanitize(test3);
string result4 = Sanitize(test4);
}
sw.Stop();
Console.WriteLine("Marc Gravell (Static Regex) way completed in " + sw.ElapsedMilliseconds.ToString() + " ms");
sw.Reset();
sw.Start();
for (idx = 0; idx < 500000; idx++)
{
string result1 = ReplaceCharsWithIndexOfAny(test1);
string result2 = ReplaceCharsWithIndexOfAny(test2);
string result3 = ReplaceCharsWithIndexOfAny(test3);
string result4 = ReplaceCharsWithIndexOfAny(test4);
}
sw.Stop();
Console.WriteLine("user1664043 (StringBuilder w/ IndexOfAny) way completed in " + sw.ElapsedMilliseconds.ToString() + " ms\n");
}
}
}
/* ... some processing ... */
部分肯定不是瓶颈,因为我以这种形式提出了问题。感谢建设性的评论。 - Dejan Janjušević