Get a function definition/implementation hint similar to the one shown in pycharm.

[hongy...@gmail.com]

On Tuesday, October 19, 2021 at 5:22:25 AM UTC+8, cameron... at gmail.com wrote:
> On 18Oct2021 01:43, Hongyi Zhao <hongy... at gmail.com> wrote: 
> >I've written the following python code snippet in pycharm: 
> >```python 
> >import numpy as np 
> >from numpy import pi, sin 
> > 
> >a = np.array([1], dtype=bool) 
> >if np.in|vert(a) == ~a: 
> > print('ok') 
> >``` 
> >When putting the point/cursor in the above code snippet at the position denoted by `|`, I would like to see information similar to that provided by `pycharm`, as shown in the following screenshots: 
> > 
> >https://user-images.githubusercontent.com/11155854/137619512-674e0eda-7564-4e76-af86-04a194ebeb8e.png 
> >https://user-images.githubusercontent.com/11155854/137619524-a0b584a3-1627-4612-ab1f-05ec1af67d55.png 
> > 
> >But I wonder if there are any other python packages/tools that can help 
> >me achieve this goal?
> Broadly, you want the "inspect" module, which is part of the stdlib, 
> documented here: https://docs.python.org/3/library/inspect.html 
> 
> It has many functions for extracting information about things, and you 
> want the signature() function to get the parameters and type annotations 
> of a function. 
> 
> def f(a): 
> ... 
> 
> sig = signature(f) 

The following ipython test failed:


In [1]: import numpy as np

In [2]: from inspect import  signature

In [3]: signature(np.invert)
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-3-f1808184276a> in <module>
----> 1 signature(np.invert)

~/.pyenv/versions/3.9.1/lib/python3.9/inspect.py in signature(obj, follow_wrapped)
   3128 def signature(obj, *, follow_wrapped=True):
   3129     """Get a signature object for the passed callable."""
-> 3130     return Signature.from_callable(obj, follow_wrapped=follow_wrapped)
   3131 
   3132 

~/.pyenv/versions/3.9.1/lib/python3.9/inspect.py in from_callable(cls, obj, follow_wrapped)
   2877     def from_callable(cls, obj, *, follow_wrapped=True):
   2878         """Constructs Signature for the given callable object."""
-> 2879         return _signature_from_callable(obj, sigcls=cls,
   2880                                         follow_wrapper_chains=follow_wrapped)
   2881 

~/.pyenv/versions/3.9.1/lib/python3.9/inspect.py in _signature_from_callable(obj, follow_wrapper_chains, skip_bound_arg, sigcls)
   2441         raise ValueError(msg)
   2442 
-> 2443     raise ValueError('callable {!r} is not supported by signature'.format(obj))
   2444 
   2445 

ValueError: callable <ufunc 'invert'> is not supported by signature




 
> You also want the function docstring for the help text, which is 
> "f.__doc__" in the example above. This is what gets printed by help(): 
> 
> >>> import numpy as np 
> >>> help(np.invert) 
> 
> It may be that PyCharm has additional information about some libraries 
> allowing it to include a reference to the only documentation. 
> 
> Cheers, 
> Cameron Simpson <c... at cskk.id.au>