String: How to replace multiple possible characters with a single character?

Question

I would like to replace all \'.\' and \' \' with a \'_\'

but I don\'t like my code...

is there a more efficient way to

Answer 1

String new_s = s.toLowerCase().replaceAll("[ .]", "_");

EDIT:

replaceAll is using regular expressions, and using . inside a character class [ ] just recognises a . rather than any character.