Difference Between Two Lists with Duplicates in Python

Question

I have two lists that contain many of the same items, including duplicate items. I want to check which items in the first list are not in the second list. For example, I mig

Answer 1

Counters are new in Python 2.7. For a general solution to substract a from b:

def list_difference(b, a):
    c = list(b)
    for item in a:
       try:
           c.remove(item)
       except ValueError:
           pass            #or maybe you want to keep a values here
    return c