Question

Trying to use backslashes in raw strings with this regular expression:

import re
print re.sub(r'^[a-zA-Z]:\\.+(\\Data.+)', r'D:\folder\1', r'C:\Some\Path\Data\File.txt')

Expected output:

D:\folder\Data\File.txt

However \f is being interpreted. Is there any way to make this work without converting to forward slashes?

Answer 1

re.sub interprets escape sequences in the replacement string (docs). Adding an extra backslash before the \f to escape the backslash seems to do the trick:

import re
print re.sub(r'^[a-zA-Z]:\\.+(\\Data.+)', r'D:\\folder\1', r'C:\Some\Path\Data\File.txt')

If your replacement string is dynamic, you can always use another regexp to escape backslashes, or use str.encode(‘unicode-escape’).