Question

我使用以下代码检查字符串是否包含在另一个字符串中 -

foreach (string testrecord in testlist)
{
   foreach (string realrecord in reallist)
   {         
      if ((Regex.Replace(testrecord , "[^0-9a-zA-Z]+", "")
                .Contains((
                    Regex.Replace(realrecord, "[^0-9a-zA-Z]+", ""))) 
          && 
           ((Regex.Replace(realrecord, "[^0-9a-zA-Z]+", "") != "") 
          && 
           ((Regex.Replace(realrecord, "[^0-9a-zA-Z]+", "").Length >= 4)))))
      {

         matchTextBox.AppendText("Match: " + testrecord + " & " + realrecord + Environment.NewLine);

      }
   }

}

然而，完成此操作的运行时间需要很长时间。由于我添加了特殊字符正则表达式删除，因此运行时间要长得多，但绝对需要正则表达式。

是否有更有效的方法来应用此正则表达式？我试图将它添加到foreach字符串变量，但是你不能改变它们，因为它们在foreach循环中。

Answer 1

优化版本：

// Do not put text into matchTextBox direct:
// it makes the control re-painting each time you change the text
// Instead, collect all the text into StringBuffer  
StringBuilder Sb = new StringBuilder(); 

// Pull out as much as you can from the inner loop,
// that's why I've changed the loops' order:
// first loop on reallist, then on testlist
foreach (string realrecord in reallist) {
  // Cache Regex.Replace result
  String realCleaned = Regex.Replace(realrecord, "[^0-9a-zA-Z]+", "");

  // Test as early as possible
  if (realCleaned.Length < 4)
    continue;

  // You don't need to test realCleaned != "";: realCleaned.Length < 4 is enough

  foreach (string testrecord in testlist) {
    // Cache Regex.Replace result: it's a little bit overshoot here, but if some
    // more tests are added it'll be helpful
    String testCleaned = Regex.Replace(testrecord, "[^0-9a-zA-Z]+", "");

    if (testCleaned.Contains(realCleaned))
      Sb.AppendLine("Match: " + testrecord + " & " + realrecord);
  }  
}

// At last matchTextBox.Text change
matchTextBox.AppendText(Sb.ToString());

Answer 2

这应该更快一点（每testrecord一个正则表达式操作）：

var strippedRealList = reallist.Select(s => Regex.Replace(s, "[^0-9a-zA-Z]+", ""))
                               .Where(s => s.Length >= 4)
                               .ToArray();

foreach (string realrecord in reallist)
{
   strippedRealList.Where(s => realrecord.Contains(s))
                   .ToList()
                   .ForEach(s =>
                            matchTextBox.AppendText("Match: "
                                                  + s
                                                  + " & "
                                                  + realrecord
                                                  + Environment.NewLine));

}

Answer 3

我想知道你正在使用正则表达式实现你的目的，忽略了你也可以通过只使用.Contains（）方法实现这一目的，这样你的代码应该比之前更简单，更快

foreach (string testrecord in testlist)
{
   foreach (string realrecord in reallist)
   {         
      if(testrecord.Contains(realrecord))
         {
         matchTextBox.AppendText("Match: " + testrecord + " & " + realrecord + Environment.NewLine);
         }
   }

}

使字符串检查更有效

3 个答案: