Regular expression to match !WSⅡ%^ OR WSⅡ in a string in C#

Question

How do I match alpahbet with roman symbol following with regular expressions.

1. I have got #!WSⅡ%^ WSⅡ ancient data =>(should match both WSⅡ)

2. I have got #!WSⅡ%^ @#WSⅡ WSⅡ ancient data =>(should match 3 times)

3. I have got AbWSⅡ WSⅡRR WSⅡ ancient data =>(should match 1 time) (AbWSⅡ WSⅡRR should not match)

I am using the following regular expression.

(?<![a-zA-Z0-9])(\\bWSⅡ\\b)(?=[a-zA-Z0-9]|)

Which is working for my all the cases except the above.

Note : Ⅱ is not II

Please help.

Thanks in advance

Answer 1

You can use

(?<![^\W_])WSⅡ(?![^\W_])

See the regex demo .

The regex matches

• (?<![^\\W_]) - a negative lookbehind that matches a location that is not immediately preceded with a char other than a non-word and _ char (so it basically requires start of string or a non-word char or _ right before)
• WSⅡ - a WSⅡ word
• (?![^\\W_]) - a negative lookahead that matches a location that is not immediately followed with a char other than a non-word and _ char (so it basically requires end of string or a non-word char or _ right after).