What is the best way to get numbers from strings?

Hi all

I have a single address sentence with housenumber in it, i want to capture just the number(s) in it. What is the best way to do this?

Example: Streetname 14 City

What I thought was:

a) replace all leters with '' and trim it after it, and parse it to integer? Should I do this by using a regex [A-Za-z] for it?

b) find just the numbers consisting from 1,2 or 3 non alphatic characters 0-9?