How to print your function's documentation python

Question

I have been searching for an answer for a lot of time now. Let's say I wrote a function in python and I made a brief documentation of what this function is doing. Is there any way to print the function's documentation from within main? Or from the function itself?

Answer 1

You can either use help() or print the __doc__. help() prints a more verbose description of an object while __doc__ holds only the documentation string you have defined with triple quotes """ """ in the beginning of your function.

For example, using __doc__ explicitly on the sum built-in function:

print(sum.__doc__)
Return the sum of a 'start' value (default: 0) plus an iterable of numbers

When the iterable is empty, return the start value.
This function is intended specifically for use with numeric values and may
reject non-numeric types.

Additionally, since Python first compiles an object and during execution evaluates it you can call __doc__ within the function with no problems:

def foo():
    """sample doc"""
    print(foo.__doc__)

foo()  # prints sample doc

and remember, besides functions, modules and classes have a __doc__ attribute holding their documentation.

Alternatively, using help() for sum:

help(sum)

Will print:

Help on built-in function sum in module builtins:

sum(iterable, start=0, /)
    Return the sum of a 'start' value (default: 0) plus an iterable of numbers

    When the iterable is empty, return the start value.
    This function is intended specifically for use with numeric values and may
    reject non-numeric types.

gives a bit more information, including the docstring.