c# - 正则表达式替换：如何在替换中动态获取匹配长度

Question

有没有办法用匹配中找到的相同长度的字符替换匹配表达式？下面的代码更容易理解：

var input = "hello hellspawn, goto hell!";
var pattern = @"(hell)(?!o)";
var replacement = "****"; // is there a dynamic way to specify length here?
var replaced = Regex.Replace(input, pattern, replacement, RegexOptions.IgnoreCase);

我可以用火柴来做到这一点：

var sbInput = new StringBuilder(input);
var sb = new StringBuilder();
var matches = Regex.Matches(input, pattern, RegexOptions.IgnoreCase);

foreach (Match match in matches) {
   sb.Length = 0;
   for (var i = 0; i < match.Length; i++) {
      sb.Append("*");
    }

    sbInput.Replace(match.Value, sb.ToString(), match.Index, match.Length);
}

var replaced = sbInput.ToString();

标签： c#.netregex

Answer 1

这应该有效：

var replaced = Regex.Replace(input, pattern,
    m => new string('*', m.Length),
    RegexOptions.IgnoreCase);