在.NET中字符串替换的五种方法

2009-05-12 22:33:28来源:未知 阅读 ()

新老客户大回馈,云服务器低至5折

1:使用String.Replace函数替换,但不支持大小写。

2:正则System.Text.Regex替换,用RegExpOption修改是否支持大小写。

3:在小数据的情况下,使用String.SubString和+可以实现间接替换。

4:导入MicrosoftVisualBasicRunTime(Microsoft.VisualBasic.DLL)使用Strings.Replace速度很快。

5:参照反射Reflector.FileDisassembler配合Strings.SplitandStrings.Join等实现,速度同5。

一下介绍一种算法,类似KMP算法。有兴趣的参照研究下。

以下为引用的内容:
privatestaticstringReplaceEx(stringoriginal,
          stringpattern,stringreplacement)
{
  intcount,position0,position1;
  count=position0=position1=0;
  stringupperString=original.ToUpper();
  stringupperPattern=pattern.ToUpper();
  intinc=(original.Length/pattern.Length)*
       (replacement.Length-pattern.Length);
  char[]chars=newchar[original.Length+Math.Max(0,inc)];
  while((position1=upperString.IndexOf(upperPattern,
                   position0))!=-1)
  {
    for(inti=position0;i<position1;++i)
      chars[count++]=original[i];
    for(inti=0;i<replacement.Length;++i)
      chars[count++]=replacement[i];
    position0=position1+pattern.Length;
  }
  if(position0==0)returnoriginal;
  for(inti=position0;i<original.Length;++i)
    chars[count++]=original[i];
  returnnewstring(chars,0,count);
}

测试

以下为引用的内容:
staticvoidMain(string[]args)
{
  stringsegment="AaBbCc";
  stringsource;
  stringpattern="AbC";
  stringdestination="Some";
  stringresult="";
  
  constlongcount=1000;
  StringBuilderpressure=newStringBuilder();
  HiPerfTimertime;
  for(inti=0;i<count;i++)
  {
    pressure.Append(segment);
  }
  source=pressure.ToString();
  GC.Collect();
  //regexp
  time=newHiPerfTimer();
  time.Start();
  for(inti=0;i<count;i++)
  {
    result=Regex.Replace(source,pattern,
         destination,RegexOptions.IgnoreCase);
  }
  time.Stop();
  Console.WriteLine("regexp  ="+time.Duration+"s");
  GC.Collect();
  //vb
  time=newHiPerfTimer();
  time.Start();
  for(inti=0;i<count;i++)
  {
    result=Strings.Replace(source,pattern,
         destination,1,-1,CompareMethod.Text);
  }
  time.Stop();
  Console.WriteLine("vb    ="+time.Duration+"s");
  GC.Collect();
  //vbReplace
  time=newHiPerfTimer();
  time.Start();
  for(inti=0;i<count;i++)
  {
    result=VBString.Replace(source,pattern,
         destination,1,-1,StringCompareMethod.Text);
  }
  time.Stop();
  Console.WriteLine("vbReplace="+time.Duration+"s");//+result);
  GC.Collect();
  //ReplaceEx
  time=newHiPerfTimer();
  time.Start();
  for(inti=0;i<count;i++)
  {
    result=Test.ReplaceEx(source,pattern,destination);
  }
  time.Stop();
  Console.WriteLine("ReplaceEx="+time.Duration+"s");
  GC.Collect();
  //Replace
  time=newHiPerfTimer();
  time.Start();
  for(inti=0;i<count;i++)
  {
    result=source.Replace(pattern.ToLower(),destination);
  }
  time.Stop();
  Console.WriteLine("Replace ="+time.Duration+"s");
  GC.Collect();
  //sorry,twoslow:(
  /*//substring
  time=newHiPerfTimer();
  time.Start();
  for(inti=0;i<count;i++)
  {
    result=StringHelper.ReplaceText(source,pattern,
         destination,StringHelper.CompareMethods.Text);
  }
  time.Stop();
  Console.WriteLine("substring="+time.Duration+":");
  GC.Collect();
  //substringwithstringbuilder
  time=newHiPerfTimer();
  time.Start();
  for(inti=0;i<count;i++)
  {
    result=StringHelper.ReplaceTextB(source,pattern,
          destination,StringHelper.CompareMethods.Text);
  }
  time.Stop();
  Console.WriteLine("substringB="+time.Duration+":");
  GC.Collect();
  */
  Console.ReadLine();
}
1?¢stringsegment="abcaBc";
regexp=3.75481827997692s
vb=1.52745502570857s
vbReplace=1.46234256029747s
ReplaceEx=0.797071415501132s!!!<FONTcolor=gray>Replace=0.178327413120941s</FONT>
//ReplaceEx>vbReplace>vb>regexp
2?¢stringsegment="abcaBcabC";
regexp=5.30117431126023s
vb=2.46258449048692s
vbReplace=2.5018721653171s
ReplaceEx=1.00662179131705s!!!
<FONTcolor=gray>Replace=0.233760994763301s</FONT>
//ReplaceEx>vb>vbReplace>regexp
3?¢stringsegment="abcaBcabCAbc";
regexp=7.00987862982586s
vb=3.61050301085753s
vbReplace=3.42324876485699s
ReplaceEx=1.14969947297771s!!!
<FONTcolor=gray>Replace=0.277254511397398s</FONT>
//ReplaceEx>vbReplace>vb>regexp
4?¢stringsegment="ABCabcAbCaBcAbcabCABCAbcaBC";
regexp=13.5940090151123s
vb=11.6806222578568s
vbReplace=11.1757614445411s
ReplaceEx=1.70264153684337s!!!(mygod!)
<FONTcolor=gray>Replace=0.42236820601501s</FONT>
//ReplaceEx>vbReplace>vb>regexp

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