求一正则表达式

Question

                                                                               <a  href="http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/2.html?province=%B1%B1%BE%A9" >2</a>
                                                                                                              <a  href="http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/3.html?province=%B1%B1%BE%A9" >3</a>
                                                                                                              <a  href="http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/4.html?province=%B1%B1%BE%A9" >4</a>
                                                                                                              <a  href="http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/5.html?province=%B1%B1%BE%A9" >5</a>
                                                                                                              <a  href="http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/6.html?province=%B1%B1%BE%A9" >6</a>
                                                                                                              <a  href="http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/7.html?province=%B1%B1%BE%A9" >7</a>求出所有的url
http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/7.html?province=%B1%B1%BE%A9
http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/6.html?province=%B1%B1%BE%A9"
                                                                                                              <a  href="http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/8.html?province=%B1%B1%BE%A9" >8</a>
                                                                                                              <a  href="http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/9.html?province=%B1%B1%BE%A9" >9</a>
                                                                  </b>...<b>      
              <a  href=" http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/2.html?province=%B1%B1%BE%A9" >

Answer 1

试试(?<=(<a  href=)).*?(?=>)

Answer 2

string regExp = @"(?<=(<a href=)).*?(?=>)";
System.Text.RegularExpressions.MatchCollection result = System.Text.RegularExpressions.Regex.Matches(@"<a href=http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/2.html?province=%B1%B1%BE%A9>2 </a>                                                                    <a  href=http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/3.html?province=%B1%B1%BE%A9  >3 </a > ", regExp);
        for (int i = 0; i < result.Count; i++)
        {
            Response.Write(result[i].ToString());
        }

Answer 3

string ttt="<a\\s+href\\s*=\\s*\"([^\"]+)\"";

string source="<a  href=\"http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/2.html?province=%B1%B1%BE%A9\"  >2 </a >"+
                       "<a  href=\"http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/3.html?province=%B1%B1%BE%A9\"  >3 </a > "+
                        "<a  href=\"http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/4.html?province=%B1%B1%BE%A9\"  >4 </a > "+
                        "<a  href=\"http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/5.html?province=%B1%B1%BE%A9\"  >5 </a > "+
                        "<a  href=\"http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/6.html?province=%B1%B1%BE%A9\"  >6 </a > "+
                        "<a  href=\"http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/7.html?province=%B1%B1%BE%A9\"  >7 </a > ";
Regex reg=new Regex(ttt);
MatchCollection mc = Regex.Matches(source,ttt,RegexOptions.IgnoreCase);
foreach (Match m in mc)
{
//Console.Write(m.Groups[0].Value + "\n");
Console.Write(m.Groups[1].Value+ "\n");
//Console.Write(m.Groups[2].Value+ "\n");
//Console.Write(m.Groups[3].Value+ "\n");
}

Answer 4

string ttt="<a\\s+href\\s*=\\s*\"([^\"]+)\"";

string source="<a  href=\"http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/2.html?province=%B1%B1%BE%A9\"  >2 </a >"+
                       "<a  href=\"http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/3.html?province=%B1%B1%BE%A9\"  >3 </a > "+
                        "<a  href=\"http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/4.html?province=%B1%B1%BE%A9\"  >4 </a > "+
                        "<a  href=\"http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/5.html?province=%B1%B1%BE%A9\"  >5 </a > "+
                        "<a  href=\"http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/6.html?province=%B1%B1%BE%A9\"  >6 </a > "+
                        "<a  href=\"http://search.china.alibaba.com/company/%E7%94%B5%E8%84%91/7.html?province=%B1%B1%BE%A9\"  >7 </a > ";
Regex reg=new Regex(ttt);
MatchCollection mc = Regex.Matches(source,ttt,RegexOptions.IgnoreCase);
foreach (Match m in mc)
{
//Console.Write(m.Groups[0].Value + "\n");
Console.Write(m.Groups[1].Value+ "\n");
//Console.Write(m.Groups[2].Value+ "\n");
//Console.Write(m.Groups[3].Value+ "\n");
}