连续删除 <br> 来自字符串使用正则表达式c＃

Question

I have following string regex

"choose to still go on the trip. <br><br>\r\nNote that when booking"

After converting it with regex I need to replace <br> tags with only one <br> so string would be like this

"choose to still go on the trip. <br>Note that when booking"

Answer 1

This can be done in another (safer) way, using HTML Agility Pack (open source project http://html-agility-pack.net ).

It takes into account the various notations <br> , <br/> , <br /> without you having to worry about it . This means you can focus on the actual task: replacing duplicates.

See Remove chain of duplicate elements with HTML Agility Pack , it explains an approach on how to replace duplicates.

Answer 2

If you need to account for the case where there is whitespace between the tags, try the following regex:

myInputStr = Regex.Replace(myInputStr,
    @"([\b\s]*<[\b\s]*[bB][rR][\s]*/?[\b\s]*>){2,}",
    "<br>", RegexOptions.Multiline);

This regex will replace 2 or more instances of <br> tags with a single instance, regardless of the formation of the tag (spacing, casing, self-closing etc.).

Answer 3

EDIT: If you don't know how many <br> you have, you can do this:

1. Split your string with <br> and remove empty entries.
2. Join the string with single <br>

Here is the code:

string yourString = "choose to still go on the trip. <br><br>\r\nNote that when booking";

var temp = 
    yourString.Split(new string[] { "<br>" }, StringSplitOptions.RemoveEmptyEntries)
               .Where(i => i.Replace(" ", string.Empty).Length > 0);

string result = string.Join("<br>", temp);

Answer 4

like Martin Eden susposed:

while (text.Contains("<br><br>")) 
{ 
    text = text.Replace("<br><br>", "<br>"); 
}    

or

string newString = oldString.Replace("<br><br><br>", "<br>");
newString = newString.Replace("<br><br>", "<br>");

do multiple such lines with increasing <br>

Answer 5

Regex.Replace(input, @"(<br\s*/{0,1}>\s*(</\s*br>)*){2,}", "<br>", 
    RegexOptions.CultureInvariant | 
    RegexOptions.IgnoreCase |
    RegexOptions.Multiline);

Replaces any two or more occurences of <br> or <br/> or <br></br> with a single <br> .

This takes whitespaces into account. <br > would match aswell as <br /> or <br > </ br> .

If you remove the unwanted "\\r\\n" beforehand you can omit RegexOptions.Multiline .