dictionary - 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 of x and y such that

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

Is it possible to do this operation? I tried update operation

x.update(y)

But it gives me the following result

z= {1:['d','e','f'],2:['g']}

Answer 1

for k, v in x.items():
if k in y.keys():
    y[k] += v
else:
    y[k] = v

Loop through dictionary getting keys and values, check if the key already exists, in which case append, else add new key with values. It won't work if your values are mixed data types that aren't lists, like you have.

   x={1:['a','b','c'], 3:['y']} 
.. y={1:['d','e','f'],2:['g']} 
..  
..  
.. for k, v in x.items(): 
..     if k in y.keys(): 
..         y[k] += v 
..     else: 
..         y[k] = v 
..      
.. print y
{1: ['d', 'e', 'f', 'a', 'b', 'c'], 2: ['g'], 3: ['y']}