To merge two dictionaries of list in Python

Question

There are two dictionaries

x={1:[\'a\',\'b\',\'c\']}
y={1:[\'d\',\'e\',\'f\'],2:[\'g\']}

I want another dictionary z which is a merged one

Answer 1

Here is a Python 3 solution for an arbitrary number of dictionaries:

def dict_merge(*dicts_list):
    result = {}
    for d in dicts_list:
        for k, v in d.items():
            result.setdefault(k, []).append(v)
    return result

Note that this solution may create lists with duplicate values. If you need unique values, use set():

def dict_merge(*dicts_list):
    result = {}
    for d in dicts_list:
        for k, v in d.items():
            result.setdefault(k, set()).add(v)
    return result