backreferences

[Iain King]

Amy Dillavou wrote:
> Can someone help me with understanding how python uses backreferences?
> I need to remember the item that was last matched by the re engine but i
> cant seem to understand anything that I find on backreferences.  if I
> want to access the last match do i use \number or is there something
> else i have to do?
>
> heres part of my code:
> renDate = re.compile("$((\d){4}-(\d){2}-(\d){2}))")
> renDate.search(l)
> if(exist.search(l) and str(lastmodDate) < \1): #i need help here with \1
>
> Thanks in advance
> A.D

I haven't had to use backreferences yet, so I don't know offhand how to
go about it.  What I do know is that this online book is very useful:

http://gnosis.cx/TPiP/


Chapter 3 covers REs:

http://gnosis.cx/TPiP/chap3.txt

>From what I remember, in python you can use numbered backreferences (up
to 99), or named ones.

Iain