CODEWITHSUNDEEP
c#regex
retide
retide

Reputation: 1190

C# Regex method explains

new Regex(@"\n|\r|\\|<|>|\*|!|\$|%|;");

I have an regex example above, but I can not really understand what is trying to find? can anyone give me a hand please?

Upvotes: 0

Views: 86

Answers (3)

Tim Pietzcker
Tim Pietzcker

Reputation: 336128

The regex matches one of the characters separated by the alternation operator |. There are a few special characters (like \n or \r for newline and carriage return, or \$ for a literal dollar sign and \* for a literal asterisk because $ and * are regex metacharacters), but other than that, it's quite straightforward.

That said, for matching a single character out of a list of valid characters, a character class is usually the better choice, not only because there is less need to escape the metacharacters:

new Regex(@"[\n\r\\<>*!$%;]");

Upvotes: 4

Rohit Jain
Rohit Jain

Reputation: 213223

| in regex is an alternation operator. A|B means match either A or B. It can also be written using a character class - [AB] which also means the same thing.

The benefit of using character class is, you don't need to escape regex meta-characters inside it, which you have to do outside, as you did for *. So, your regex can be shortened to:

new Regex(@"[\n\r\\<>*!$%;]");

Upvotes: 2

Stephane Delcroix
Stephane Delcroix

Reputation: 16232

It'll try to match any of the special character listed: \n, \r, \, <, >, *, !, $, % The | is the regex OR operator.

Some characters need to be escaped with an extra \ as they have a signification in the regex lanugage (\, $, ...)

Upvotes: 2

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