inner sublist positions ?

[tiissa]

Bernard A. wrote:
> maybe have you some better / faster ideas / implementations ? or even
> a more pythonic to help me learning that

You may want to look at string matches algorithm (a good review: [1]).
In particular there are classics like Boyer-Moore and some involving
minimal automatons similar to your regular expression ideas.

[1] http://www-igm.univ-mlv.fr/~lecroq/string/index.html