How do I concisely write x = x - 4 unless x is less than 0, in which case x = 0?

Question

I am doing some pagination and can do @next_images_to_paginate += 4 without a problem.

But @previous_images_to_paginate -= 4 doesn't because I can get negative numbers.

I can't use absolute because I want -1, -2 and -3 to be 0.

Something like:

((@previous_images_to_paginate -= 4) < 0) ? 0 : (@previous_images_to_paginate -= 4)

but I would like something less wordy.

The page being created is not appropriate for will_paginate, etc.

Answer 1

How about using the max function from an array

x = [x-4,0].max