正则表达式选项匹配多行并忽略大小写 [英] Regex options matching multi-line as well as ignoring the case

问题描述

我有一些格式不正确的html，有时"丢失了.此外，它有时会显示大写字母，而有时会显示小写字母:

I have some piece of ill-formed html, sometimes the " is missing. Also, it sometimes shows capital cases while other times lower cases:

<DIV class="main">
    <DIV class="subsection1">
   <H2>
   <DIV class=subwithoutquote>StackOverflow</DIV></H2></DIV></DIV>

我想同时匹配多行并忽略大小写.但是以下模式似乎不起作用. (对于串联，我也尝试了|而不是&)

I would like to match both multi-line and ignoring the case. But the following patern does not seem to be working. (For the concatenation, I also tried | instead of &)

const string pattern = @"<div class=""?main""?><div class=""?subsection1""?><h2><div class=""?subwithoutquote""?>(.+?)</div>";
Match m = Regex.Match(html, pattern, RegexOptions.IgnoreCase & RegexOptions.Singleline);

还是应该在模式中添加\ n *来解决多行问题?

Or should I add \n* in the pattern to solve multi-line issue?

推荐答案

第一个问题是，制表符之间的正则表达式中不允许使用空格.正确的正则表达式(经过Rubular测试)是:

The first problem is that you are not allowing for white-space in your regex between tabs. The correct regex (tested in Rubular) is:

<div class=""?main""?>\s*<div class=""?subsection1""?>\s*<h2>\s*<div class=\"?subwithoutquote\"?>(.+?)<\/div>\s*

请注意添加了几个\s*条目.

Notice the addition of several \s* entries.

第二个问题是您没有正确连接选项.

The second problem is that you're not concatenating the options properly.

您的代码:

Match m = Regex.Match(html, pattern, RegexOptions.IgnoreCase & RegexOptions.Singleline);

因为这些是位标志，所以按位与(&运算符)是错误的标志.您想要的是按位或(|运算符).

Since these are bit flags, Bitwise-And (& operator) is a wrong flag. What you want is Bitwise-Or (| operator).

按位运算符-表示如果在其中的 中都设置了该位，请将其保留；否则，将其取消设置.您需要按位运算或，这意味着"如果该位在其中的 中设置，请进行设置；否则，请取消设置."

Bitwise-And means "if the bit is set in both of these, leave it set; otherwise, unset it. You need Bitwise-Or, which means "if the bit is set in either of these, set it; otherwise, unset it."

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