Python. How to subtract 2 dictionaries

I have 2 dictionaries, A and B. A has 700000 key-value pairs and B has 560000 key-values pairs. All key-value pairs from B are present in A, but some keys in A are duplicates with different values and some have duplicated values but unique keys. I would like to subtract B from A, so I can get the remaining 140000 key-value pairs. When I subtract key-value pairs based on key identity, I remove lets say 150000 key-value pairs because of the repeated keys. I want to subtract key-value pairs based on the identity of BOTH key AND value for each key-value pair, so I get 140000. Any suggestion would be welcome.

This is an example:

A = {'10':1, '11':1, '12':1, '10':2, '11':2, '11':3}
B = {'11':1, '11':2}

I DO want to get: A-B = {’10’:1, ’12’:1, ’10’:2, ’11’:3}

I DO NOT want to get:

a) When based on keys:

{'10':1, '12':1, '10':2}

or

b) When based on values:

{'11':3}

Answer

A = {'10':1, '11':1, '12':1, '10':2, '11':2, '11':3}
B = {'11':1, '11':2}

You can’t have duplicate keys in Python. If you run the above, it will get reduced to:

A={'11': 3, '10': 2, '12': 1}
B={'11': 2}

But to answer you question, to do A – B (based on dict keys):

all(map( A.pop, B))   # use all() so it works for Python 2 and 3.
print A # {'10': 2, '12': 1}