raw string

Il faut utiliser des raw strings

In [1]: import re
 
In [2]: re.sub('pattern', r'\\test', 'replace the pattern by \\test')
Out[2]: 'replace the \\test by \\test'
 
In [3]: re.sub('pattern', r'\\lest', 'replace the pattern by \\lest')
Out[3]: 'replace the \\lest by \\lest'
 
In [4]: re.sub('pattern', r'\\nest', 'replace the pattern by \\nest')
 Out[4]: 'replace the \\nest by \\nest'

http://docs.python.org/reference/lexical_analysis.html#string-literals

Matthieu Gautier|irc:starmad