Regular expression that matches a string containing only certain letters

Question

I've tried several combinations of regex to figure this out, but some or the condition doesn't work,

I have an input string that can only contain a specific set of specific characters

lets say A, B or C.

how can I match something like this?

ABBBCCC - isMatch True

AAASDFDCCC - isMatch false

ps. I am using C #

+2

81967 21 Sep '09 at 6:34

2 answers

I think you are looking for this:


Match m = Regex.Match("abracadabra", "^[ABC]*$");
if (m.Success) {
   // Macth
}

+1

NawaMan 21 Sep '09 at 6:38

VonC · Accepted Answer · 2009-09-21T06:36:54+0000

 ^[ABC]+$

Anchors '^' and '$' will only be available to ensure that the entire string contains only those characters from start to end.

Regex.Match("ABACBA", "^[ABC]+$"); // => matches

Meaning: The character set does not guarantee the order in which the characters match.

Regex.Match("ABACBA", "^A+B+C+$"); // => false

Guaranteed order