Negative Look Ahead Python Regex

I would like to regex match a sequence of bytes when the string '02 d0' does not occur at a specific position in the string. The position where this string of two bytes cannot occ

Solution 1:

Lookaheads are "zero-width", meaning they do not consume any characters. For example, these two expressions will never match:

1. (?=foo)bar
2. (?!foo)foo

To make sure a number is not some specific number, you could use:

(?!42)\d\d # will match two digits that are not 42

In your case it could look like:

(?!02)[\da-f]{2} (?!0d)[\da-f]{2}

or:

(?!02 d0)[\da-f]{2} [\da-f]{2}