How to exclude files using find

Question

Unlike the --exclude parameter for rsync that can excludes both files and directories, the *nix find command's -prune parameter can only exclude directories.

So how can I exclude a certain type of files (say .bak) when invoking find?
In other words, how to make the following non-working example works?

find --exclude=*.bak /some/dir

Thanks

Answer 1

If I understand the question properly, the following will work:

find /some/dir \! -name '*.bak'

Answer 2

find . -type f \( ! -iname "*.bak" \)