find difference of values between 2 array of objects in python

Question

I have 2 array of objects:

a = [{'a': 1, 'b': 2}, {'c': 3, 'd': 4}, {'e': 5, 'f': 6}]
b = [{'a': 1, 'b': 2}, {'g': 3, 'h': 4}, {'f': 6, 'e': 5}]

Output:
a - b = [{'c': 3, 'd': 4}] ("-" symbol is only for representation, showing difference. Not mathematical minus.)
b - a = [{'g': 3, 'h': 4}]

In every array, the order of key may be different. I can try following and check for that:

for i in range(len(a)):
   current_val = a[i]
   for x, y in current_val.items:
      //search x keyword in array b and compare it with b

but this approach doesn't feel right. Is there simpler way to do this or any utility library which can do this similar to fnc or pydash?

Answer 1

You can use lambda:

g = lambda a,b : [x for x in a if x not in b]

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g(a,b) # a-b

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[{'c': 3, 'd': 4}]

---

---

g(b,a) # b-a

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[{'g': 3, 'h': 4}]