python merge dictionaries

z = {**x, **y}

dict1 = {'a': 10, 'b': 8} 
dict2 = {'d': 6, 'c': 4} 
dict2.update(dict1)

dict1 = {'color': 'blue', 'shape': 'square'}
dict2 = {'color': 'red', 'edges': 4}

dict1.update(dict2) #if a key exists in both, it takes the value of the second dict
# dict1 = {'color': 'red', 'shape': 'square', 'edges': 4}
# dict2 is left unchanged

z = {**x, **y}

>>> from collections import ChainMap
>>> a = [{'a':1},{'b':2},{'c':1},{'d':2}]
>>> dict(ChainMap(*a))
{'b': 2, 'c': 1, 'a': 1, 'd': 2}

>>> x = {'a': 1, 'b': 2}
>>> y = {'b': 10, 'c': 11}
>>> z = {**x, **y} #In Python 3.5 or greater only
>>> print(z)
{'a': 1, 'b': 10, 'c': 11}

dic0.update(dic1)

def mergeDict(dict1, dict2):
   ''' Merge dictionaries and keep values of common keys in list'''
   dict3 = {**dict1, **dict2}
   for key, value in dict3.items():
       if key in dict1 and key in dict2:
               dict3[key] = [value , dict1[key]]
 
   return dict3
 
# Merge dictionaries and add values of common keys in a list
dict3 = mergeDict(dict1, dict2)
 
print('Dictionary 3 :')
print(dict3)