Subtracting two lists in Python

Question

In Python, How can one subtract two non-unique, unordered lists? Say we have a = [0,1,2,1,0] and b = [0, 1, 1] I\'d like to do something like

Answer 1

I'm not sure what the objection to a for loop is: there is no multiset in Python so you can't use a builtin container to help you out.

Seems to me anything on one line (if possible) will probably be helishly complex to understand. Go for readability and KISS. Python is not C :)