[英]How to perform multiple Regex replacements in sequence from a list of unique items cleanly in C#
我试图找到一种更简洁的方法来对单个字符串执行多个顺序替换,其中每个替换都有唯一的模式和字符串替换。
例如,如果我有 3 对模式替换字符串:
1. /(?<,\\)\\n/, "\n"
2. /(\\)(?=[\;\:\,])/, ""
3. /(\\{2})/, "\\"
我想在原始字符串上应用正则表达式替换 1,然后在 1 的 output 上应用 2,依此类推。
下面的控制台程序示例正是我想要的,但它有很多重复,我正在寻找一种更简洁的方法来做同样的事情。
清理字符串
static public string SanitizeString(string param)
{
string retval = param;
//first replacement
Regex SanitizePattern = new Regex(@"([\\\;\:\,])");
retval = SanitizePattern.Replace(retval, @"\$1");
//second replacement
SanitizePattern = new Regex(@"\r\n?|\n");
retval = SanitizePattern.Replace(retval, @"\n");
return retval;
}
解析命令
static public string ParseCommands(string param)
{
string retval = param;
//first replacement
Regex SanitizePattern = new Regex(@"(?<!\\)\\n");
retval = SanitizePattern.Replace(retval, System.Environment.NewLine);
//second replacement
SanitizePattern = new Regex(@"(\\)(?=[\;\:\,])");
retval = SanitizePattern.Replace(retval, "");
//third replacement
SanitizePattern = new Regex(@"(\\{2})");
retval = SanitizePattern.Replace(retval, @"\");
return retval;
}
主要的
using System;
using System.IO;
using System.Text.RegularExpressions;
...
static void Main(string[] args)
{
//read text that contains user input
string sampleText = File.ReadAllText(@"c:\sample.txt");
//sanitize input with certain rules
sampleText = SanitizeString(sampleText);
File.WriteAllText(@"c:\sanitized.txt", sampleText);
//parses escaped characters back into the original text
sampleText = ParseCommands(sampleText);
File.WriteAllText(@"c:\parsed_back.txt", sampleText);
}
不要介意文件操作。 我只是用它作为可视化实际 output 的快速方法。 在我的程序中,我将使用不同的东西。
这是一种方法:
var replacements = new List<(Regex regex, string replacement)>()
{
(new Regex(@"(?<!\\)\\n"), System.Environment.NewLine),
(new Regex(@"(\\)(?=[\;\:\,])"), ""),
(new Regex(@"(\\{2})"), @"\"),
};
(理想情况下将其缓存在 static 只读字段中):
然后:
string retval = param;
foreach (var (regex, replacement) in replacements)
{
retval = regex.Replace(retval, replacement);
}
或者你可以 go 沿着 linq 路线:
string retval = replacements
.Aggregate(param, (str, x) => x.regex.Replace(str, x.replacement));
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