Combine two lists of dictionaries into one list of dictionaries, where a primary_key is used to join the dictionaries between them

zip_two_lists_of_dictionaries.py

from collections import defaultdict

""" 
    Zip is at the dict level - if only some of the dicts in a lod have a key, 
        only resultant dicts with one of their primary_keys will have that given k:v pair
    When both lods have a given (non-primary) key, the lod_2 value is prioritized.
    Originally from https://stackoverflow.com/questions/5501810/join-two-lists-of-dictionaries-on-a-single-key
"""
def zip_lods(lod_1, lod_2, primary_key, **kwargs):

    d = defaultdict(dict)
    for l in (lod_1, lod_2):
        for elem in l:
            if kwargs.get("keys_subset_list") and primary_key in kwargs['keys_subset_list']:
               elem =  {k:v for k,v in elem.items() if k in kwargs['keys_subset_list']}
            elif kwargs.get("keys_subset_list"):
                raise ValueEror("Check your keys_subset - it needs to have the primary_key and be a list")

            d[elem[primary_key]].update(elem)

    output_lod = list(d.values())
    return output_lod