c# - 交替替换子字符串

Question

我想知道是否有任何方法可以替换字符串中的子字符串，但在字符串之间交替替换它们。 I.E，匹配所有出现的字符串 "**"并将第一次出现的替换为 "<strong>"下一次出现 "</strong>" (然后重复该模式)。

输入将是这样的:"This is a sentence with **multiple** strong tags which will be **strong** upon output"

返回的输出为:"This is a sentence with <strong>multiple</strong> strong tags which will be <strong>strong</strong> upon output"

Answer 1

您可以使用带有 MatchEvaluator 委托(delegate)的 Regex.Replace 重载:

using System.Text.RegularExpressions;

class Program {
    static void Main(string[] args) {
        string toReplace = "This is a sentence with **multiple** strong tags which will be **strong** upon output";
        int index = 0;
        string replaced = Regex.Replace(toReplace, @"\*\*", (m) => {
            index++;
            if (index % 2 == 1) {
                return "<strong>";
            } else {
                return "</strong>";
            }
        });
    }
}