c# - C#正则表达式如何进行这种匹配

Question

请帮我解决问题，非常感谢

string=
"
<span id="thread_aaaa" class="tsubject">
    <a href="viewthread.php?tid=12343245&amp;extra=page%3D1"> 
        WHAT I WANT TO GET1 
    </a>
</span>

<span id="thread_bbbb" class="tsubject">
    <a href="viewthread.php?tid=65456342&amp;extra=page%3D1">
        WHAT I WANT TO GET2
    </a>
</span>
"

我需要获得 WHAT I WANT TO GET1 、 WHAT I WANT TO GET2 等的值

我正在使用： ( " < span id=\"thread_)(.+?)< /a>< /span>")，但不起作用，求助

Answer 1

对于给出的新示例字符串，这将找到它们：

string str = @"
< span id=""thread_aaaa"" class=""tsubject"" >< a href=""viewthread.php?tid=12343245&extra=page%3D1"" > WHAT I WANT TO GET1 < /a >< / span>

< span id=""thread_bbbb"" class=""tsubject"">< a href=""viewthread.php?tid=65456342&extra=page%3D1"" >WHAT I WANT TO GET2</a>< /span>";

Regex regex1 = new Regex(@"href.*>(.*)< *\/a");
var matches = regex1.Matches(str);

foreach (var m in matches)
{
    var match = (Match) m;
    Console.WriteLine(match.Groups[1].Value.Trim()); // write the value to the console "pattern"
}

/*
Output:
WHAT I WANT TO GET1 
WHAT I WANT TO GET2
*/

Answer 2

您正在寻找的正则表达式是：

(?<=aaa)(.*)(?=bbb)

// 匹配两个字符串 aaa 和 bbb 之间的任何字符