How can I dynamically call built in methods such as doc in Python 3?

Question

I am new to Python and I was printing the __doc__ of various built-in Python methods. Then I tried to do the following:

for f in dir(__builtins__):
    print('********' + f + '********\n', f.__doc__)

I was surprised when the result of this looked something like this:

********abs********
    str(object='') -> str
    str(bytes_or_buffer[, encoding[, errors]]) -> str
********all********
    str(object='') -> str
    str(bytes_or_buffer[, encoding[, errors]]) -> str
********any********
    str(object='') -> str
    str(bytes_or_buffer[, encoding[, errors]]) -> str
********ascii********
    str(object='') -> str
    str(bytes_or_buffer[, encoding[, errors]]) -> str

After doing some research, I found this, but I still didn't see how I could do what I was hoping to accomplish. I know that this is seamlingly pointless, but I feel it will be useful for me to understand how to dynamically execute tasks similar to this in Python.

Thank you for the help!

score 4 · Accepted Answer · answered Dec 24 '18 at 03:31

4

dir(__builtins__) (also iterating over a module) gives the names in the module to get the objects one has to use getattr:

for f in dir(__builtins__):
    print('********' + f + '********\n', getattr(__builtins__, f).__doc__)

answered Dec 24 '18 at 03:31

Dan D.

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score 1 · Answer 2 · answered Dec 24 '18 at 03:30

In your for loop, you are not getting the actual functions/methods when you call

for f in dir(__builtins__):

Instead, each time f is just a string with the name of the function/method. So when you call:

f.__doc__

You are always getting back the docstring for str types. It is no different than calling:

'abc'.__doc__

How can I dynamically call built in methods such as __doc__ in Python 3?

2 Answers2

How can I dynamically call built in methods such as doc in Python 3?