Question

I want to find strings that do NOT match a particular sequence of characters. For example:

something like

REGEX = r'[^XY]*'

I’d like to look for strings that have any number of characters except an X and Y next to each other…the REGEX above doesn’t work since it blocks X’s and Y’s separately.

Answer 1

How about:

if "XY" not in s:
   print "matched"
else
   print "not matched"

Or is this for inclusion in some longer regexp? Then maybe you want a negative lookahead expression:

REGEXP="...(?!XY)..."

EDIT: fixed typo