Jon Clements wrote: > (I reckon this is probably a question for MRAB and is not really > Python specific, but anyhow...) > > Absolutely basic example: re.sub(r'(\d+)', r'\1', 'string1') > > I've been searching around and I'm sure it'll be obvious when it's > pointed out, but how do I use the above to replace 1 with 11? > Obviously I can't use r'\11' because there is no group 11. I know I > can use a function to do it, but it seems to me there must be a way > without. Can I escape r'\11' somehow so that it's group 1 with a '1' > after it (not group 11).
Quoting http://docs.python.org/library/re.html#re.sub """ In addition to character escapes and backreferences as described above, \g<name> will use the substring matched by the group named name, as defined by the (?P<name>...) syntax. \g<number> uses the corresponding group number; \g<2> is therefore equivalent to \2, but isn’t ambiguous in a replacement such as \g<2>0. \20 would be interpreted as a reference to group 20, not a reference to group 2 followed by the literal character '0'. The backreference \g<0> substitutes in the entire substring matched by the RE. """ Peter -- http://mail.python.org/mailman/listinfo/python-list