Python student seeks help regex/strings

[Petyr David]

I'm familiar with simple string substitutions in shell and perl:

string= "I have 30 days to find it"

echo $string | sed "s/\(.*\)\(30\)\(.*\)/\2/

which will (if I did it right) leave 30

and perl likewise.

I'm having trouble figuring out how to do this in Python and it's not
for lack of trying to find an example. It can't be this hard is it?

Hopefully I will limit my newbie questions.

Thanks

Peter