Remove some characters from an string

Question

I have a string, something like this: rgb (255, 0, 0). And I want to remove every character inside it except numbers and the , (comma) character.

I have two questions based on this:

How to do that with Regex? (I found this answer, but I don't know how to include the , (comma) sign into it...)
Is Regex the best method for this purpose? Or there is some other (better) methods?

(Best = having best performance)

"but I don't know how to include the , (comma) sign into it..." It doesn't take a lot of research and/or trial and error to find out. — Niklas B., Aug 29 '12 at 15:11
Quick and dirty `string.Replace("rgb (", "").Replace(")","");` — dtsg, Aug 29 '12 at 15:12
You can use regexto extractthe numbers, rather than remove unwanted chars — craig1231, Aug 29 '12 at 15:12
Oded's answer was the best: `var clean = myString.Replace("01234567890, ".ToCharArray(), string.Empty);`, but he has deleted his answer. I don't know why... — Mahdi Ghiasi, Aug 29 '12 at 15:14
Yeah, true, this will do the exact opposite of what you want. — Niklas B., Aug 29 '12 at 15:17

score 8 · Accepted Answer · answered Aug 29 '12 at 15:12

8

Regex is the easiest, surely:

Regex.Replace(s, "[^\d,]+", "")

will replace everything that is not a digit or a comma.

answered Aug 29 '12 at 15:12

Joey

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score 3 · Answer 2 · edited May 23 '17 at 11:49

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Use the same approach as in the question you referenced:

Regex rgx = new Regex("[^\d,]");

str = rgx.Replace(str, string.Empty);

edited May 23 '17 at 11:49

Community

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answered Aug 29 '12 at 15:13

Bernard

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score 1 · Answer 3 · answered Aug 29 '12 at 15:24

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Regex is a very viable solution.

I would set my pattern to (?<colour>(\d*), ?(\d*), ?(\d*)) allowing for optional spaces before each colour digit but does not limit to maximum 3 numbers per digit (a further tweak could rectify this).

You would then access the colour as a group.

Regex pattern = new Regex(@"(?<colour>(\d*), ?(\d*), ?(\d*))");
Match m = pattern.Match(color);
Console.WriteLine(m.Groups["colour"].ToString());

Returns: 255, 0, 0

answered Aug 29 '12 at 15:24

Lewis Harvey

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After viewing the question, I see performance was a requirement so I test the two and the results are not what I expected. Regex replace is faster up to 8 times! Full test code can be found at http://lewisharvey.wordpress.com/2012/08/29/regex-replace-vs-regex-match-and-group-performance/ – Lewis Harvey Aug 29 '12 at 15:48
Performance test results location changed: http://justcodesomething.wordpress.com/2012/08/29/regex-replace-vs-regex-match-and-group-performance/ – Lewis Harvey Dec 05 '13 at 08:51

Remove some characters from an string

3 Answers3