如何在C＃.net中使用正则表达式替换组值

Question

我有一个像

string s= "I WAS born in AMERICA on december 1978.";

现在我想使用正则表达式将12 月转换为12月

我在下面使用了不完整的正则表达式

s=Regex.Replace(s,(january|february|march|April|may|june|july|august|september|October|november|December),CultreInfo.InvariantCulture.TextInfo.ToTitleCase(?????),RegexOption.IgnoreCase);

我必须在这里写什么（?????），这样我才能得到以下输出

s= "I WAS born in AMERICA on December 1978.";

我还有其他方法可以申请吗？

Answer 1

查看regex.replace文档，我注意到您必须使用回调函数。

所以写一个函数：

function CustomReplace( Match m ) {
    return CultreInfo.InvariantCulture.TextInfo.ToTitleCase(m.Groups[1].Value)
}

并将其作为第三个参数传递：

s = Regex.Replace(
    s,
    "(january|february|march|April|may|june|july|august|september|October|november|December)",
    CustomReplace,
    RegexOption.IgnoreCase
);

Answer 2

使用命名的捕获和内联MatchEvaluator ：

string s = "I WAS born in AMERICA on december 1978.";
s = Regex.Replace(
    s,
    "(?<months>january|february|march|April|may|june|july|august|september|October|november|December)",
    new MatchEvaluator(
        match => CultureInfo
                .InvariantCulture
                .TextInfo
                .ToTitleCase(match.Groups["months"].Value)
    ),
    RegexOptions.IgnoreCase
);