My Regex.Replace doesn't work

Question

hey I am currently trying to replace html in a string. I.e <strong>text</strong> needs to be <b>text</b> etc. (I realize the b tag is considered outdated)

I am aware that I shouldn't use regex to fix this, but this is currently my only option

my code:

//replace strong
text = Regex.Replace(text, "<strong>.*?</strong>", "<b>$1</b>");

//replace em
text = Regex.Replace(text, "<em>.*?</em>", "<i>$1</i>");

the issue here is that the regex replaces the tags and sets the text to $1. how to avoid this? (I'm in C# btw.)

Richard · Accepted Answer · 2013-01-28 11:54:44Z

5

The $1 will use the value of the first capture in the match. But you have not specified any capturing groups in the match, so there is nothing for $1 to subtitute.

Use (…) to capture in a regex expression:

text = Regex.Replace(text, "<strong>(.*?)</strong>", "<b>$1</b>");

answered Jan 28, 2013 at 11:54

Richard

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daryal · Accepted Answer · 2013-01-28 11:58:06Z

2

Note that the following answer is just a workaround; it is better to write a proper regex.

var text = "<strong>asfdweqwe121</strong><em>test</em>";

text = text.Replace("<strong>", "<b>");
text = text.Replace("</strong>", "</b>");
text = text.Replace("<em>", "<i>");
text = text.Replace("</em>", "</i>");

answered Jan 28, 2013 at 11:58

daryal

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Wiktor Stribiżew · Accepted Answer · 2021-10-21 12:56:16Z

0

You can also consider using:

text = Regex.Replace(text, "<strong>(.*?)</strong>", "<b>$1</b>", RegexOptions.Singleline);

Note that RegexOptions.Singleline is necessary to allow . to match line feed (LF, \x0A) characters, that the . pattern cannot match by default.

answered Oct 21, 2021 at 12:56

Wiktor Stribiżew

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