替换除 <pre> 标签之间的换行符答案

【问题标题】：Replace line breaks except for ones between <pre> tags替换除 <pre> 标签之间的换行符
【发布时间】：2014-01-17 14:27:06
【问题描述】：

我希望替换/删除给定字符串中的所有换行符，但嵌套在<pre> 标记中的换行符除外。所以对于以下字符串：

var text = @"
    Some contents which is formatted
    over multiple
    lines but contains a 
    <pre>
        tag which has
        also has
        multiple line breaks.
    </pre>
";

我想删除所有换行符，除了嵌套在 pre 标记中的换行符：

Regex.Replace(text, "\n", "<br />");

【问题讨论】：

标签： c# html regex replace

【解决方案1】：

使用消极的前瞻性，你仍然可以在一行中做到：

text = Regex.Replace(text, "\n(?![^<]*</pre>)", "<br />");

这里有一些测试代码，更好的示例包含多个<pre> 标签：

var text = @"
    Some contents which is formatted
    over multiple
    lines but contains a 
    <pre>
        tag which has
        also has
        multiple line breaks.
    </pre>
    foo 1
    bar 1
    <pre>
        tag which has
        also has
        multiple line breaks.
    </pre>
    foo 2
    bar 2
";
text = Regex.Replace(text, "\n(?![^<]*</pre>)", "<br />");
Console.WriteLine(text);

输出：

<br />    Some contents which is formatted<br />    over multiple<br />    lines but contains a <br />    <pre>
    tag which has
    also has
    multiple line breaks.
</pre><br />    foo 1<br />    bar 1<br />    <pre>
    tag which has
    also has
    multiple line breaks.
</pre><br />    foo 2<br />    bar 2<br />

【讨论】：

【解决方案2】：

不漂亮，但对我有用。

    static void Main(string[] args)
        {
            var text = @"
    Some contents which is formatted
    over multiple
    lines but contains a 
    <pre>
        tag which has
        also has
        multiple line breaks.
    </pre>
";
            int pre_tag_ini = text.IndexOf("<pre>");
            int pre_tag_fim = text.IndexOf("</pre>");
            string result = Regex.Replace(text.Substring(0, pre_tag_ini), "\r\n", "<br />");
            result += text.Substring(pre_tag_ini, pre_tag_fim - pre_tag_ini);;
            result += Regex.Replace(text.Substring(pre_tag_fim, text.Length - pre_tag_fim), "\r\n", "<br />");

            Console.Write(result);
            Console.ReadLine();
        }

【讨论】：

如果您将文本视为 HTML 并使用 HTML Agility Pack，可能会有一种优雅的方式来执行此操作，但对于给定的内容，这是可行的。