通过按特定标签拆分字符串来获取字符串列表

Question

我想通过特定标签将字符串拆分为列表或数组。

<START><A>message<B>UnknownLengthOfText<BEOF><AEOF><A>message<B>UnknownLengthOfText<BEOF><AEOF><END>

我想把上面的例子分成两个项目，项目是<A>和<AEOF>标签之间的字符串

感谢任何帮助。

Answer 1

我建议为此使用简单的正则表达式。 看看这个例子：

using System.Diagnostics;
using System.Text.RegularExpressions;

...

Regex regex = new Regex("<A>(.*?)<B><BEOF>(.*?)<AEOF>");
string myString = @"<START><A>message<B><BEOF>UnknownLengthOfText<AEOF><A>message<B><BEOF>some other line of text<AEOF><END>";
MatchCollection matches = regex.Matches(myString);
foreach (Match m in matches)
{
    Debug.WriteLine(m.Groups[1].ToString(), m.Groups[2].ToString());
}

编辑：

由于字符串在一行，正则表达式应该是“惰性的”，用惰性量词? 标记。另外，我更改了正则表达式，以便它使用 sTrenat 的建议来自动解析消息和标题。

所以，而不是

Regex regex = new Regex("<A>(.*)<AEOF>");

我用过

Regex regex = new Regex("<A>(.*?)<B><BEOF>(.*?)<AEOF>");

注意额外的?标记惰性量词，当它找到标签之间的第一个匹配时停止（没有?整个字符串将被捕获，而不是标签之间的n消息）

Answer 2

试试这样的：

string test = @"<START>
                   <A>message<B><BEOF>UnknownLengthOfText<AEOF>
                   <A>message<B><BEOF>UnknownLengthOfText<AEOF>
                <END>";

//for this test this will give u an array containing 3 items...
string[] tmp1 = test.Split("<AEOF>");

//here u will store your results in
List<string> results = new List<string>();

//for every single one of those 3 items:
foreach(string item in tmp1)
{
     //this will only be true for the first and second item
     if(item.Contains("<A>"))
     {
           string[] tmp2 = item.Split("<A>");

           //As the string you are looking for is always BEHIND the <A> you 
           //store the item[1], (the item[0] would be in front)

           results.Add(tmp2[1]);
     }
}

Answer 3

您可以使用 Regex.Split 而不是使用 String.Split，如下所示

        var stringToSplit = @"<START>
                                <A>message<B>UnknownLengthOfText<BEOF><AEOF>
                                <A>message<B>UnknownLengthOfText<BEOF><AEOF>
                            <END>";

        var regex = "<A>(.*)<AEOF>";
        var splitStrings = Regex.Split(stringToSplit, regex);

splitStrings 将包含 4 个元素

splitString[0] = "<START>"
splitString[1] = "message<B>UnknownLengthOfText<BEOF>"
splitString[2] = "message<B>UnknownLengthOfText<BEOF>"
splitString[3] = "<END>"

使用正则表达式只能给你和之间的字符串

Answer 4

到目前为止，所有答案都是基于正则表达式的。这是一个没有的替代方案：

Try it Online!

    var input = @"
<START>
    <A>message<B>UnknownLengthOfText<BEOF><AEOF>
    <A>message<B>UnknownLengthOfText<BEOF><AEOF>
<END>";
    var start = "<A>";
    var end = "<AEOF>";
    foreach (var item in ExtractEach(input, start, end))
    {
        Console.WriteLine(item);
    }
}

public static IEnumerable<string> ExtractEach(string input, string start, string end)
{
    foreach (var line in input
             .Split(Environment.NewLine.ToCharArray())
             .Where(x=> x.IndexOf(start) > 0 && x.IndexOf(start) < x.IndexOf(end)))
    {
        yield return Extract(line, start, end);
    }
}


public static string Extract(string input, string start, string end)
{
    int startPosition = input.LastIndexOf(start) + start.Length;
    int length = input.IndexOf(end) - startPosition;
    var substring = input.Substring(startPosition, length);
    return substring;
}