Search for books on one shelf but not another

[Diana]

I love being able to look at multiple shelves, but I wish I could also chose to view books on one shelf but not another.

For example, I'm updating my shopping list before an upcoming sale and would like to view by to-read but not those I have shelved under "owned."

Or is there a way to do this that I missed?

Thanks!

[Alexis]

I haven't seen any api's that let you specify more than one shelf, or exclude some shelves. The only thing I could think to do is first get all of the "to-read" books, then filter out the ones that say "owned." It would be really useful to be able to exclude shelves; I've thought about this just on the website too, but especially in a program!