How to merge two dicts and combine common keys?

Question

I would like to know how if there exists any python function to merge two dictionary and combine all values that have a common key.

I have found function to append t

Answer 1

If you meant to use actual dicts, instead of lists of dicts, this is easier.

D1 = dict(k1=1, k3=3, k4=4)
D2 = dict(k1=11, k2=12, k4=14)

There isn't a simple built-in function to do this, but the setdefault method is close. It tries to get the given key, but creates it if it doesn't exist.

D3 = {}
for k, v in D1.items() | D2.items():
    D3.setdefault(k, set()).add(v)

And the result.

{'k4': {4, 14}, 'k1': {1, 11}, 'k3': {3}, 'k2': {12}}

This all assumes the order doesn't matter, just combining sets.