In [1]:

    

from inspect import signature


    

In [2]:

    

def f(a, b, c=1):
    pass


    

In [3]:

    

sig = signature(f)


    

In [12]:

    

params = sig.parameters
params


    

    
Out[12]:





mappingproxy({'a': <Parameter "a">,
              'b': <Parameter "b">,
              'c': <Parameter "c=1">})

In [13]:

    

a = sig.parameters['a']


    

In [14]:

    

a.name


    

    
Out[14]:





'a'

In [15]:

    

a.kind


    

    
Out[15]:





<_ParameterKind.POSITIONAL_OR_KEYWORD: 1>

In [16]:

    

a.default


    

    
Out[16]:





inspect._empty

In [17]:

    

c = sig.parameters.get('c')


    

In [18]:

    

c.default


    

    
Out[18]:





1

In [37]:

    

sig.bind?


    

In [31]:

    

# Bind to type
bind = sig.bind(str, int, int)


    

In [32]:

    

bind.arguments


    

    
Out[32]:





OrderedDict([('a', str), ('b', int), ('c', int)])

In [33]:

    

bind.arguments.get('a')


    

    
Out[33]:





str

In [34]:

    

bind.arguments['a']


    

    
Out[34]:





str

In [27]:

    

sig.bind(str)


    

    




---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-27-4a46b925cd4f> in <module>()
----> 1 sig.bind(str)

/home/wukai/.pyenv/versions/miniconda3-latest/envs/cv3/lib/python3.5/inspect.py in bind(*args, **kwargs)
   2918         if the passed arguments can not be bound.
   2919         """
-> 2920         return args[0]._bind(args[1:], kwargs)
   2921 
   2922     def bind_partial(*args, **kwargs):

/home/wukai/.pyenv/versions/miniconda3-latest/envs/cv3/lib/python3.5/inspect.py in _bind(self, args, kwargs, partial)
   2833                             msg = 'missing a required argument: {arg!r}'
   2834                             msg = msg.format(arg=param.name)
-> 2835                             raise TypeError(msg) from None
   2836             else:
   2837                 # We have a positional argument to process

TypeError: missing a required argument: 'b'

In [30]:

    

print(sig.bind_partial.__doc__)


    

    




Get a BoundArguments object, that partially maps the
        passed `args` and `kwargs` to the function's signature.
        Raises `TypeError` if the passed arguments can not be bound.
        

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