PYTHON
Merging Multiple Dictionaries Using Python's `**` Operator
Combine several Python dictionaries into a single one efficiently using the dictionary unpacking (`**`) operator, perfect for configuration management or data aggregation.
# Define several dictionaries
defaults = {
"host": "localhost",
"port": 8000,
"debug": False
}
user_settings = {
"port": 8080,
"debug": True
}
environment_vars = {
"host": "production.server.com"
}
# Method 1: Using the dictionary unpacking operator (Python 3.5+)
# Later dictionaries' keys override earlier ones
final_config = {**defaults, **user_settings, **environment_vars}
print("Merged config (Method 1):")
print(final_config)
# Expected: {'host': 'production.server.com', 'port': 8080, 'debug': True}
# Method 2: Using dict.update() (modifies the first dict or a copy)
config_update_method = defaults.copy() # Make a copy to avoid modifying original
config_update_method.update(user_settings)
config_update_method.update(environment_vars)
print("
Merged config (Method 2 - update()):")
print(config_update_method)
# Method 3: Using the union operator (Python 3.9+)
# config_union_method = defaults | user_settings | environment_vars
# print("
Merged config (Method 3 - union operator):")
# print(config_union_method)
How it works: This snippet demonstrates common ways to merge multiple Python dictionaries. The most modern and concise approach (Python 3.5+) uses the dictionary unpacking operator (`**`), where keys from later dictionaries in the expression override those from earlier ones. An alternative is using `dict.update()`, which modifies an existing dictionary. These techniques are highly useful for combining configuration settings, request parameters, or data from various sources in web applications. (Note: The dictionary union operator `|` is for Python 3.9+ and is commented out for broader compatibility, as the prompt specifies "Python 3.5+" in the code comments).