CODEWITHSUNDEEP
c#regex
Frank Myat Thu
Frank Myat Thu

Reputation: 4474

Special string replace function

I have to replace specific links with the link which I pre-defined.

string content = @"<html>"
                +" <a href='http://www.yourdomain.com' style='width:10px;'>Click Here</a>"
                +" <br>"
                +" <a href='http://www.yourdomain.com/products/list.aspx' style='width:10px;'>Click Here</a>"
                +" </html>";

To be replaced like this ===> "http://www.yourdomain.com" to "http://www.mydomain.com"

But I don't want other link which also start with "http://www.yourdomain.com" to be replaced. If these links has a sub link (i.e., "/products/list.aspx").

So I use C# string.Replace() function first.

string result = content.Replace("http://www.yourdomain.com", "http://www.mydomain.com");

I also try Regex.Replace() function as well.

string pattern = @"\bhttp://www.yourdomain.com\b";
string replace = "http://www.mydomain.com";
string result = Regex.Replace(content, pattern, replace);

But I got same result. like below.

<html> 
<a href='http://www.mydomain.com' style='width:10px;'>Click Here</a> 
<br> 
<a href='http://www.mydomain.com/products/list.aspx' style='width:10px;'>Click Here</a> 
</html>

What I want is like below.

<html> 
<a href='http://www.mydomain.com' style='width:10px;'>Click Here</a> 
<br> 
<a href='http://www.yourdomain.com/products/list.aspx' style='width:10px;'>Click Here</a> 
</html>

Update

According to @Robin suggestion, my problem is solved.

string content = @"<html>"
                    +" <a href='http://www.yourdomain.com' style='width:10px;'>Click Here</a>"
                    +" <br>"
                    +" <a href='http://www.yourdomain.com/products/list.aspx' style='width:10px;'>Click Here</a>"
                    +" </html>";

string pattern = string.Format("{0}(?!/)", "http://www.yourdomain.com");
string replace = "http://www.mydomain.com";
string result = Regex.Replace(content, pattern, replace);

Update

Another alternative way which I found is

http://www.yourdomain.com([^/])

Upvotes: 1

Views: 114

Answers (2)

Robin
Robin

Reputation: 9644

Apart from the usual warning about dealing with HTML using regex, a word boundary \b matches between an alphanum (\w) and a non alphanum (\W), so it matches both between m and ' and between m and /.

To explicitly forbid a / after the end of the URL you can use a negative lookahead, see here:

 http://www.yourdomain.com(?!/)

Upvotes: 1

Hjalmar Z
Hjalmar Z

Reputation: 1601

Add ''s at the ends of your string arguments in the replace call.

result = content.Replace("'http://www.yourdomain.com'", "'http://www.mydomain.com'");

That way you would only replace the urls without sub links.

Upvotes: 2

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