PYTHON
Merge Multiple Dictionaries in Python
Discover various Python techniques to efficiently merge several dictionaries into one, handling potential key conflicts and ensuring desired output for combined data structures.
dict1 = {'a': 1, 'b': 2}
dict2 = {'c': 3, 'd': 4}
dict3 = {'e': 5, 'a': 6} # Note: 'a' is a conflicting key
# Method 1: Using ** operator (Python 3.5+)
merged_dict_1 = {**dict1, **dict2, **dict3}
print(f"Merged with **: {merged_dict_1}")
# Method 2: Using dict.update() (modifies in place or new dict)
merged_dict_2 = dict1.copy() # Start with a copy to avoid modifying original
merged_dict_2.update(dict2)
merged_dict_2.update(dict3)
print(f"Merged with update(): {merged_dict_2}")
# Method 3: Using | operator (Python 3.9+)
merged_dict_3 = dict1 | dict2 | dict3
print(f"Merged with |: {merged_dict_3}")
# Output will prioritize keys from rightmost dictionaries in case of conflict:
# Merged with **: {'a': 6, 'b': 2, 'c': 3, 'd': 4, 'e': 5}
# Merged with update(): {'a': 6, 'b': 2, 'c': 3, 'd': 4, 'e': 5}
# Merged with |: {'a': 6, 'b': 2, 'c': 3, 'd': 4, 'e': 5}
How it works: This snippet showcases three common ways to merge multiple dictionaries in Python. The `**` operator (unpacking) and the `|` operator (union, Python 3.9+) create new dictionaries and are generally preferred for their conciseness. The `dict.update()` method modifies an existing dictionary in place. In all methods, if keys conflict (like 'a' in the example), values from the rightmost or latest merged dictionary take precedence.