C# 在一个字符串中一次做很多替换

Question

我有一个替换字典

var substitutions = new Dictionary<string, string>()
{
    { "one", "two" },
    { "two", "three" },
};

我想把字符串“一二三四”变成“二三三四”。

运行任何类型的迭代替换链，例如

var phrase = "one two three four";
substitutions.Aggregate(phrase, (current, substitution) => current.Replace(substitution.Key, substitution.Value)));

或

var sb = new StringBuilder(phrase);
foreach (var entry in substitutions)
{
    sb.Replace(entry.Key, entry.Value);
}
sb.ToString();

产生“三三三四”，因为第二个替换“二”→“三”能够从前一个输出中看到“一”→“二”输出。

如何只替换“原始”字词？

Answer 1

您可以按如下方式使用正则表达式:

var substitutions = new Dictionary<string, string>()
{
    { "one", "two" },
    { "two", "three" },
};

var phrase = "one two three four";

var pattern = string.Join("|", substitutions.Keys.Select(Regex.Escape));

// Pattern is: one|two

var result = Regex.Replace(phrase, pattern, match => substitutions[match.Value]);

Working example

---

如果替换必须只匹配完整的单词，您可以更新 pattern 以包含单词边界 \b:

substitutions.Keys.Select(x => @$"\b{Regex.Escape(x)}\b")

Working example