How to Pass a Single Dictionary Instead of Many Arguments into a Function in Python

on the usefulness of calling function(**arguments)

The aim of this page📝 is to learn from this encounter in code that goes something like

options = {
    "statsd_host": os.environ["STATSD_HOST"],
    "statsd_port": int(os.environ["STATSD_PORT"])
}

datadog.initialize(**options)

• In summary, this is a pretty cool way of passing concise function calls (Uncle Bob would cap the arg count to 3)
• The code means that the initialize() the method must contain parameters called statsd_host, statsd_port
• And, surely, statsd_host and statsd_port are listed as params in the monstrous function in the API docs:

datadog.initialize(api_key=None, app_key=None, host_name=None, api_host=None, >>> statsd_host=None, statsd_port=None <<<, statsd_disable_buffering=True, statsd_use_default_route=False, statsd_socket_path=None, statsd_namespace=None, statsd_constant_tags=None, return_raw_response=False, hostname_from_config=True, **kwargs)

• The called method initialize() is mapping the dictionary keys from the options variable to parameter names within its own function definition and thus accessing passed values
• The coolness is that you can then extend the options dictionary without modifying the function call
• As a side note, note the permissiveness of the initialize() function:

1. none of the arguments are required as all have a default value set to None
2. There also is **kwargs at the end of the function definition; i.e. you can pass a random number of dictionaries

LINKS

• https://pavolkutaj.medium.com/use-kwargs-to-accept-an-arbitrary-number-of-keyword-arguments-b6711ff8090a
• https://medium.com/p/13a82675f026
• https://datadogpy.readthedocs.io/en/latest/#datadog.initialize
• https://medium.com/mindorks/how-to-write-clean-code-lessons-learnt-from-the-clean-code-robert-c-martin-9ffc7aef870c#41e3