String negation using regular expressions

Question

Is it possible to do string negation in regular expressions? I need to match all strings that do not contain the string \"..\". I know you can use ^[^\\

Answer 1

You can use negative lookaheads:

^(?!.*\.\.).*$

That causes the expression to not match if it can find a sequence of two periods anywhere in the string.

Answer 2

^(?:(?!\.\.).)*$

will only match if there are no two consecutive dots anywhere in the string.