Merge multiple dictionaries Python code example

Example 1: join two dictionaries python

z = {**x, **y}

Example 2: python merge two dictionaries in a single expression

z = {**x, **y}  #python 3.5 and above

z = x | y    #python 3.9+ ONLY

def merge_two_dicts(x, y): # python 3.4 or lower
      z = x.copy()   # start with x's keys and values
      z.update(y)    # modifies z with y's keys and values & returns None
      return z

Example 3: merge two dict python 3

z = {**x, **y}

Example 4: merge a list of dictionaries python

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

Example 5: python merge dictionaries

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

Example 6: merge multile dict

dict1 = {"a":1, "b":2}
dict2 = {"x":3, "y":4}
merged = {**dict1, **dict2}
print(merged) # {'a': 1, 'b': 2, 'x': 3, 'y': 4}