I'm a newbie in bash and I would like to pass as parameter to a python function all files in a directory that don't match a given pattern. sth. like:
$myscripts/myprog.py $myfiles/!(bonjovi)
The above example should retrieve all files that don't match to "bonjovi".
Best wishes
You have the syntax exactly right. You just need to enable it.
shopt -s extglob 
It's probably easiest to use grep, xargs and a regular expression. grep -v excludes lines (in this case filenames) matching a given pattern.
ls | grep -v 'bonjovi' | xargs myscripts/myprog.py 
*bonjovi_album1* isn't a valid regular expression because there's nothing before the first *. echo bonjovi_album1 | grep -v 'bonjovi_album1*' works for me but it might not be doing what you expect. It removes anything containing bonjovi_album followed by 0 or more 1 s. In this case it's equivalent to the pattern bonjovi_album.