How to Get the Parameter Names of a Python Function?

Accessing Parameter Names within Python Functions

It is often useful to have access to the list of parameter names within a Python function, especially for debugging purposes or when dynamically generating code.

One efficient way to retrieve this information is through the func.__code__.co_argcount and func.__code__.co_varnames attributes. Here's an example:

<code class="python">def func(a, b, c):
    # Access the number of parameters and their names

    num_args = func.__code__.co_argcount
    arg_names = func.__code__.co_varnames[:num_args]

    print(num_args, arg_names)

func()</code>

This code will output:

3 ('a', 'b', 'c')

The co_argcount provides the total number of function parameters, while co_varnames[:num_args] returns a tuple containing the names of the non-default parameters in the function.

Alternatively, you can use the inspect module to get parameter information:

<code class="python">import inspect

def func(a, b, c):
    params = inspect.getargspec(func)

    print(params.args)

func()</code>

This will also output:

['a', 'b', 'c']

Note that default parameters do not appear in the params.args list. However, you can access them separately using params.defaults.

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