Python string pattern recognition/compression

Question

I can do basic regex alright, but this is slightly different, namely I don\'t know what the pattern is going to be.

For example, I have a list of similar strings:

<

Answer 1

How about subbing out the known text, and then splitting?

import re
[re.sub('(sometxt|moretxt)', ',', x).split(',') for x in lst]
# results in
[['a', '0', ''], ['b', '1', ''], ['aa', '10', ''], ['zz', '999', '']]