Search through string and replace parts of the string

Question

I have a string that contains some random text plus 0 or more span tags.

Like this.

Hey <span class="OverLayStyle" style="background-color:#d8dfea">@Peter</span> and <span class="OverLayStyle" style="background-color:#d8dfea">@cara</span> 

Do you like <span class="OverLayStyle" style="background-color:#d8dfea">#Facebook</span>  or <span class="OverLayStyle" style="background-color:#d8dfea">#Google</span> ?

I would like to pull out the span tag that contains a @ and replace it with an a tag like this:

<span class="OverLayStyle" style="background-color:#d8dfea">@Peter</span>

TO:

<a href="" class="OverLayStyle" style="background-color:#d8dfea">@Peter</a>

Is it possible to do something like this?

I tried indexOf(), Contains(), but all the code i wrote got so big to even be good. — , Oct 23 '15 at 07:50
@FarhanAnam Or it could make things [worse](http://stackoverflow.com/a/1732454/67392): it depends on how random the "some random text" is. Generally an HTML Parser should be used for manipulation of HTML, but if the change is narrowly scoped and specific regular expressions can be a reasonable approach. — Richard, Oct 23 '15 at 09:27
@Richard the regex is just to match the span tags, independent of the 'random text'. — Fᴀʀʜᴀɴ Aɴᴀᴍ, Oct 23 '15 at 10:47

Jeroen van Langen · Accepted Answer · 2015-10-23T08:24:19.490

You could do something like:

var line = @"
<span class=""OverLayStyle"" style=""background-color:#d8dfea"">@Peter</span>
<span class=""OverLayStyle"" style=""background-color:#d8dfea"">Peter</span>
<span class=""OverLayStyle"" style=""background-color:#d8dfea"">someone@example.com</span>
<span class=""OverLayStyle"" style=""background-color:#d8dfea"">@Peter</span>";

var replaced = Regex.Replace(
    line,
    "<span.*?>@+.*?</span>",
    match => match.Value
             .Replace("span ", "a href=\"\" ")
             .Replace("/span>", "/a>"));


Gives:
  <a href="" class="OverLayStyle" style="background-color:#d8dfea">@Peter</a>
  <span class="OverLayStyle" style="background-color:#d8dfea">Peter</span>
  <span class="OverLayStyle" style="background-color:#d8dfea">someone@example.com</span>
  <a href="" class="OverLayStyle" style="background-color:#d8dfea">@Peter</a>

This will only replace the span tag when it's content starts with @

If I understand the problem correctly, the OP wants to replace the ` — Shnugo, Oct 23 '15 at 08:09

score 2 · Answer 2 · answered Oct 23 '15 at 08:04

You could try this:

    string s1="Hey <span class=\"OverLayStyle\" style=\"background-color:#d8dfea\">@Peter</span> and <span class=\"OverLayStyle\" style=\"background-color:#d8dfea\">@cara</span>";
    string s2 = "Do you like <span class=\"OverLayStyle\" style=\"background-color:#d8dfea\">#Facebook</span>  or <span class=\"OverLayStyle\" style=\"background-color:#d8dfea\">#Google</span> ?";

    var sb=new StringBuilder();

    var parts = s1.Split(new string[] { "</span>" },StringSplitOptions.RemoveEmptyEntries);
    foreach (var s in parts) {
        if (s.Contains('@'))
            sb.Append(s.Replace("<span ", "<a href=\"\" ") + "</a>");
        else
            sb.Append(s + "</span>"); 
    }

    var resultOfs1 = sb.ToString();
    /*
    Hey <a href="" class="OverLayStyle" style="background-color:#d8dfea">@Peter</a> and <a href="" class="OverLayStyle" style="background-color:#d8dfea">@cara</a> 
    */

    sb.Clear();

    parts = s2.Split(new string[] { "</span>" }, StringSplitOptions.RemoveEmptyEntries);
    foreach (var s in parts) {
        if (s.Contains('@'))
            sb.Append(s.Replace("<span ", "<a href=\"\" ") + "</a>");
        else
            sb.Append(s + "</span>");
    }
    var resultOfs2 = sb.ToString();
    /*
    Do you like <span class="OverLayStyle" style="background-color:#d8dfea">#Facebook</span>  or <span class="OverLayStyle" style="background-color:#d8dfea">#Google</span> ?</span> 
    */

This will fail when using an email adress: like: `someone@whatever.com` — Jeroen van Langen, Oct 23 '15 at 08:17
This is true, but the OP did not state anything like that... It would be easy to get the line with `s.Contains` more specifif if needed. Btw: I like your approach, one up vote from my side... — Shnugo, Oct 23 '15 at 08:18
I think your solution is straight forward. Normally Regex will make things more difficult. +1 for you.. — Jeroen van Langen, Oct 23 '15 at 08:20
Yes it would be that easy probably... Hey, now the accepted one flipped over to you... Happy coding! — Shnugo, Oct 23 '15 at 08:24

score -1 · Answer 3 · answered Oct 23 '15 at 08:02

-1

Have you tried string.Replace? :

string v=yourString.Replace(@"<span",@"yourReplacement"); string v2=yourString.Replace(@"</span",@"yourReplacement");

To avoid any error you have to assign to a new string

Source: http://www.dotnetperls.com/replace

answered Oct 23 '15 at 08:02

Mihai-Daniel Virna

984
9
19

Does this as i said, look for those span tags that only contains a @ – Carsten Løvbo Andersen Oct 23 '15 at 08:04
It will replace the closing tag but you can put that in your replacement string. The problem is that you have to have a difference between what you want to replace then you would just replace span and get everywhere the same string. – Mihai-Daniel Virna Oct 23 '15 at 08:07

Search through string and replace parts of the string

3 Answers3