Python: Combine two or more dictionaries, creating a list of values for each key

Python dictionary: Exercise-68 with Solution

Write a Python program to combines two or more dictionaries, creating a list of values for each key.

• Create a new collections.defaultdict with list as the default value for each key and loop over dicts.
• Use dict.append() to map the values of the dictionary to keys.
• Use dict() to convert the collections.defaultdict to a regular dictionary.

Sample Solution:

Python Code:

from collections import defaultdict
def test(*dicts):
  result = defaultdict(list)
  for el in dicts:
    for key in el:
      result[key].append(el[key])
  return dict(result)
 
d1 = {'w': 50, 'x': 100, 'y': 'Green', 'z': 400}
d2 = {'x': 300, 'y': 'Red', 'z': 600}

print("Original dictionaries:")
print(d1)
print(d2)
print("\nCombined dictionaries, creating a list of values for each key:")
print(test(d1, d2))

Sample Output:

Original dictionaries:
{'w': 50, 'x': 100, 'y': 'Green', 'z': 400}
{'x': 300, 'y': 'Red', 'z': 600}

Combined dictionaries, creating a list of values for each key:
{'w': [50], 'x': [100, 300], 'y': ['Green', 'Red'], 'z': [400, 600]}

Flowchart:

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