Efficiently Merging Dictionaries (Python 3.5+)
Owner: SnippetBot
Created: 2026-07-30 00:00:24
Size: 1.22 KB
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# Method 1: Using the ** operator (Python 3.5+)
dict1 = {'a': 1, 'b': 2}
dict2 = {'c': 3, 'd': 4}
merged_dict_1 = {**dict1, **dict2}
print(f"Merged using **: {merged_dict_1}")
# Expected: {'a': 1, 'b': 2, 'c': 3, 'd': 4}
# Handling overlapping keys - later dictionary wins
dict3 = {'a': 5, 'e': 6}
merged_dict_2 = {**dict1, **dict2, **dict3}
print(f"Merged with overlap using **: {merged_dict_2}")
# Expected: {'a': 5, 'b': 2, 'c': 3, 'd': 4, 'e': 6}
# Method 2: Using the | operator (Python 3.9+)
dict4 = {'x': 10, 'y': 20}
dict5 = {'z': 30, 'x': 40} # Overlapping key 'x'
merged_dict_3 = dict4 | dict5
print(f"Merged using | (Python 3.9+): {merged_dict_3}")
# Expected: {'x': 40, 'y': 20, 'z': 30} (dict5's 'x' wins)
# In-place merge/update using |= (Python 3.9+)
dict_to_update = {'color': 'red', 'size': 'medium'}
updates = {'size': 'large', 'price': 100}
dict_to_update |= updates
print(f"In-place update using |=: {dict_to_update}")
# Expected: {'color': 'red', 'size': 'large', 'price': 100}
# Method 3 (older, less concise): Using .update()
dict_old_method = {'key1': 'val1'}
dict_old_method.update({'key2': 'val2', 'key1': 'new_val1'})
print(f"Merged using .update(): {dict_old_method}")
# Expected: {'key1': 'new_val1', 'key2': 'val2'}