Working with named groups in re module

[Fredrik Lundh]

Neil Cerutti wrote:

> A found some clues on lexing using the re module in Python in an
> article by Martin L÷wis.

>   Here, each alternative in the regular expression defines a
>   named group. Scanning proceeds in the following steps:
>
>      1. Given the complete input, match the regular expression
>      with the beginning of the input.
>      2. Find out which alternative matched.

you can use lastgroup, or lastindex:

http://effbot.org/zone/xml-scanner.htm

there's also a "hidden" ready-made scanner class inside the SRE module
that works pretty well for simple cases; see:

http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/457664

</F>