hi,
I want to downcase a string but without specific parts.
for example:
msg = "THIS is a Text and (NO Change HERE) HELP"

after downcase it should look like "this is a text and (NO Change HERE)
help"

I don't want to downcase the letters in parentheses.
How can i do that, i  tried it with regular expressions but can't do
it. 

Thanks for any help