什么是C#Regex相当于Java的appendReplacement和appendTail

Question

UPDATE

这就是我想出的.我还没有测试它,因为它是仍然需要移植的更大代码段的一部分.

你能看到任何看起来不合适的东西吗？

private const string tempUserBlock = "%%%COMPRESS~USER{0}~{1}%%%";
string html = "some html";
int p = 0;
var userBlock = new ArrayList();

MatchCollection matcher = preservePatterns[p].Matches(html);
int index = 0;
StringBuilder sb = new StringBuilder();
int lastValue = 0;

foreach(Match match in matcher){
    string matchValue = match.Groups[0].Value;

    if(matchValue.Trim().Length > 0) {
        userBlock.Add(matchValue);

        int curIndex = lastValue + match.Index;
        sb.Append(html.Substring(lastValue, curIndex));
        sb.AppendFormat(tempUserBlock, p, index++);

        lastValue = curIndex + match.Length;
    }
}

sb.Append(html.Substring(lastValue));
html = sb.ToString();

---

以下原始帖子:

这是原始的Java:

private static final String tempUserBlock = "%%%COMPRESS~USER{0}~{1}%%%";
String html = "some html";
int p = 0;
List<String> userBlock = new ArrayList<String>();

Matcher matcher = patternToMatch.matcher(html);
int index = 0;
StringBuffer sb = new StringBuffer();
while (matcher.find())
{
    if (matcher.group(0).trim().length() > 0)
    {
        userBlock.add(matcher.group(0));
        matcher.appendReplacement(sb, MessageFormat.format(tempUserBlock, p, index++));
    }
}
matcher.appendTail(sb);
html = sb.toString();

到目前为止我的C#转换

private const string tempUserBlock = "%%%COMPRESS~USER{0}~{1}%%%";
string html = "some html";
int p = 0;
var userBlock = new ArrayList();

MatchCollection matcher = preservePattern.Matches(html);
int index = 0;
StringBuilder sb = new StringBuilder();

for(var i = 0; i < matcher.Count; ++i){
    string match = matcher[i].Groups[0].Value;
    if(match.Trim().Length > 0) {
        userBlock.Add(match);
        // WHAT DO I DO HERE?
        sb.Append( string.Format(tempUserBlock, p, index++) );            
    }
}
// WHAT DO I DO HERE?
matcher.appendTail(sb);
html = sb.toString();

请参阅上面的评论,在那里我问,"我在这做什么？"

澄清
上面的Java代码在某些HTML上执行字符串替换.它保存了最初替换的文本,因为在完成一些空格压缩后需要重新插入.

Answer 1

没有必要重现Java的appendReplacement/appendTail功能; .NET有更好的东西:MatchEvaluator.看看这个:

string holder = "Element {0} = {1}";
string s0 = "111 222 XYZ";
ArrayList arr = new ArrayList();

string s1 = Regex.Replace(s0, @"\d+",
  m => string.Format(holder, arr.Add(m.Value), m.Value)
);

Console.WriteLine(s1);
foreach (string s in arr)
{
  Console.WriteLine(s);
}

输出:

Element 0 = 111 Element 1 = 222 XYZ
111
222

有几种方法可以实现MatchEvaluator,所有这些都在本文中进行了详细讨论.这个(lambda表达式)是迄今为止最酷的.