好的，有很多正则表达式，但一如既往，它们似乎都不符合我的目的。
我有一个文本文件：
F00220034277909272011
H001500020003000009272011
D001500031034970000400500020000000025000000515000000000
D001500001261770008003200010000000025000000132500000000
H004200020001014209272011
D004200005355800007702200005142000013420000000000000000
D004200031137360000779000005000000012000000000000000000
H050100180030263709272011
D050100001876700006000300019500000025000000250000001500
D050100001247060000071500030000000025000000280000000000
D050100002075670000430400020000000025000000515000000000
D050100008342500007702600005700000010000000000000000700
D050100009460270000702100015205000025000000000000006205
D050100008135120000702400015000000010000000000000001000
D050100006938430000702200026700000010000000000000001000
D050100006423710008000200025700000000000000000000001000
D050100009488040008000600007175000000000000000000001000
D050100001299190000800100016300000000000000000000003950
D050100001244850000800400005407000000000000000000001607
D050100001216280000840200020000000000000001000000006200
D050100001216840000479000008175000000000000100000001000
D050100001265880000410200014350000000000000100000001000
D050100007402650002000300026700000000000000100000001000
D050100001305150002000200016175000000000001000000000000
D050100005435430000899700022350000000000001000000000000
D050100031113850000500200008200000000250000100000001000
并且，使用多行正则表达式（.NET风格），我想做一个替换，以便得到：
H050100180030263709272011
D050100001876700006000300019500000025000000250000001500
D050100001247060000071500030000000025000000280000000000
D050100002075670000430400020000000025000000515000000000
D050100008342500007702600005700000010000000000000000700
D050100009460270000702100015205000025000000000000006205
D050100008135120000702400015000000010000000000000001000
D050100006938430000702200026700000010000000000000001000
D050100006423710008000200025700000000000000000000001000
D050100009488040008000600007175000000000000000000001000
D050100001299190000800100016300000000000000000000003950
D050100001244850000800400005407000000000000000000001607
D050100001216280000840200020000000000000001000000006200
D050100001216840000479000008175000000000000100000001000
D050100001265880000410200014350000000000000100000001000
D050100007402650002000300026700000000000000100000001000
D050100001305150002000200016175000000000001000000000000
D050100005435430000899700022350000000000001000000000000
D050100031113850000500200008200000000250000100000001000
因此，基本上，我抓住以[HD]0501开头的所有内容。
我知道这似乎更适合替换的匹配，但我正在通过一个预先构建的引擎，只接受正则表达式模式字符串和正则表达式替换字符串。
我可以为模式和替换字符串提供什么来获得我想要的结果？ Multiline Regex是一种硬编码配置吗？
我原本以为这样的事情会起作用：
搜索：
(?<Match>^[HD]0501\d+$)，但这没有任何匹配。
搜索：
(?!^[HD]0501\d+$)，但这匹配了一堆空字符串，我无法弄清楚要替换字符串的内容。
搜索：
(?!(?<Omit>^[HD]0501\d+$))，“未找到群组'省略'。”
看起来这应该很简单，但一如既往，Regex设法让我感到愚蠢。非常感谢帮助。
答案 0 :(得分：3)
尝试匹配以下模式：
(?m)^(?![HD]0501).+(\r?\n)?
并用空字符串替换它。
以下演示：
using System;
using System.Text.RegularExpressions;
namespace Test
{
class MainClass
{
public static void Main (string[] args)
{
string input = @"F00220034277909272011
H001500020003000009272011
D001500031034970000400500020000000025000000515000000000
D001500001261770008003200010000000025000000132500000000
H004200020001014209272011
D004200005355800007702200005142000013420000000000000000
D004200031137360000779000005000000012000000000000000000
H050100180030263709272011
D050100001876700006000300019500000025000000250000001500
D050100001247060000071500030000000025000000280000000000
D050100002075670000430400020000000025000000515000000000
D050100008342500007702600005700000010000000000000000700
D050100009460270000702100015205000025000000000000006205
D050100008135120000702400015000000010000000000000001000
D050100006938430000702200026700000010000000000000001000
D050100006423710008000200025700000000000000000000001000
D050100009488040008000600007175000000000000000000001000
D050100001299190000800100016300000000000000000000003950
D050100001244850000800400005407000000000000000000001607
D050100001216280000840200020000000000000001000000006200
D050100001216840000479000008175000000000000100000001000
D050100001265880000410200014350000000000000100000001000
D050100007402650002000300026700000000000000100000001000
D050100001305150002000200016175000000000001000000000000
D050100005435430000899700022350000000000001000000000000
D050100031113850000500200008200000000250000100000001000";
string regex = @"(?m)^(?![HD]0501).+(\r?\n)?";
Console.WriteLine(Regex.Replace(input, regex, ""));
}
}
}
打印：
H050100180030263709272011
D050100001876700006000300019500000025000000250000001500
D050100001247060000071500030000000025000000280000000000
D050100002075670000430400020000000025000000515000000000
D050100008342500007702600005700000010000000000000000700
D050100009460270000702100015205000025000000000000006205
D050100008135120000702400015000000010000000000000001000
D050100006938430000702200026700000010000000000000001000
D050100006423710008000200025700000000000000000000001000
D050100009488040008000600007175000000000000000000001000
D050100001299190000800100016300000000000000000000003950
D050100001244850000800400005407000000000000000000001607
D050100001216280000840200020000000000000001000000006200
D050100001216840000479000008175000000000000100000001000
D050100001265880000410200014350000000000000100000001000
D050100007402650002000300026700000000000000100000001000
D050100001305150002000200016175000000000001000000000000
D050100005435430000899700022350000000000001000000000000
D050100031113850000500200008200000000250000100000001000
快速解释：
(?m)
^匹配新行的开头; ^
(?![HD]0501)
"H0501"或"D0501"; .+
(\r?\n)?