antirice's advice is a great way of doing it. But there's only one problem. The original post suggested that the outcome from "ThisString" should be "this" and "string" (note the upper case delimeters have become lower case).

Not wanting to abandon antirice's efficient advice, I would suggest just doing this:

print map lc split/(?=[A-Z])/,"ThisString";
print map lc split/(?=[A-Z])/,"SomeOtherString";
__DATA__
output:
this string
some other string
[download]

Dave

"If I had my life to do over again, I'd be a plumber." -- Albert Einstein