使用C＃的正则表达式：如何替换与特定组匹配的字符串

Question

给出2组的正则表达式：

Regex regex = new Regex("^[^{}]*(\\{([^}]*)\\})[^{}]*$"); // group 1 matches {exp} (with braces)
                                                          // group 2 matches exp   (without braces)

如何替换第一组中的匹配？

string inputStr = "mystring{valueToRaplace}"
string s = regex .Replace(inputStr, m => ???);

例如，我想指定是否匹配并替换{valueToRaplace}（组1）或valueToRaplace（组2）。

Answer 1

我认为这就是你想要的

Regex regex = new Regex("^[^{}]*(\\{([^}]*)\\})[^{}]*$"); 
string inputStr = "mystring{valueToRaplace}";
string replaceWithThis = "Replace with this";

//change m.Groups[2] to whichever index you want to replace
string final = regex.Replace(inputStr, 
                    new MatchEvaluator(new Func<Match, string>(m => inputStr.Replace(m.Groups[2].Value, replaceWithThis))));