.NET RegEx help

Question

Hi All, I am very inexperienced when it comes to regular expressions. What I'm trying to do is iterate through a list of strings and try to locate strings that are of a certain pattern. The strings I am interested in will be in the form of "some text ***{some text}***" How do I write a RegEx to match up to? I was trying this:

Regex expression = new Regex("***");

but this gives me an error. parsing "***" - Quantifier {x,y} following nothing.

Can someone point me in the right direction?

I'm trying to loop through select list options and add a css class to the options that are relevant.

Regex expression = new Regex("***");
foreach (ListItem li in listItemCollection)
{
    if (expression.IsMatch(li.Value))
        li.Attributes.Add("class", "highlight1");
}

but this obviously isn't working.

Any help is appreciated, ~ck in San Diego

Answer 1

You need to escape the asterisk, as it's a valid metacharacter in RegExp.

Regex expression = new Regex(@"\*\*\*");

Answer 2

* has a special meaning in regular expression.

If you are looking to match 3 asteriks, try

Regex expression = new Regex(@"\*\*\*");

EDIT:

If you are only trying to verify if a string contains "***", look at bdukes' answer.

Answer 3

Try something like this:

\*\*\*[^\*]+\*\*\*

Answer 4

If you are going to test out regexes, get an application for testing. Any of these would be a good start. I've been attached to Chris Sells's tester for a long time but there are lots out there.

Answer 5

If all you're trying to do is match three asterisks, why not just use the string.Contains method instead of a regular expression?

foreach (ListItem li in listItemCollection)
{
    if (li.Value.Contains("***"))
        li.Attributes.Add("class", "highlight1");
}

Answer 6

You should try this regex pattern

\*{3}\{[^\}]*}\*{3}

This will find ***{some text}***

If you want the text before the * you should use this one

^[\w\s]*\*{3}\{[^\}]*\}\*{3}

• ^ - beginning of the input
• [\w\s]* any char in a-z, A-Z, 0-9, _ and white space, 0 or more times
• \*{3} three asterisks
• \{ match {
• [^\}]* any char except } 0 or more times
• \} match }
• \*{3} match three asterisks

Answer 7

Others have already offered valid suggestions for how to solve your specific problem. I want to respond to your comment "Hi All, I am very inexperienced when it comes to RegularExpressions." It is impossible to over recommend Jeffrey Friedl's Mastering Regularing Expressions. This is a top five book for all programmers.