Get Keyword Arguments for Function, Python

Question

def thefunction(a=1,b=2,c=3):
    pass

print allkeywordsof(thefunction) #allkeywordsof doesnt exist

which would give [a,b,c]

Is there a function like allkeywordsof?

I cant change anything inside, thefunction

duplicate of http://stackoverflow.com/questions/2677185/how-read-method-signature — Xavier Combelle, Aug 11 '12 at 13:23
possible duplicate of [Getting method parameter names in python](http://stackoverflow.com/questions/218616/getting-method-parameter-names-in-python) — Marcin, Aug 11 '12 at 17:58

unutbu · Answer 1 · 2012-08-11T13:43:34.800

24

I think you are looking for inspect.getargspec:

import inspect

def thefunction(a=1,b=2,c=3):
    pass

argspec = inspect.getargspec(thefunction)
print(argspec.args)

yields

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

If your function contains both positional and keyword arguments, then finding the names of the keyword arguments is a bit more complicated, but not too hard:

def thefunction(pos1, pos2, a=1,b=2,c=3, *args, **kwargs):
    pass

argspec = inspect.getargspec(thefunction)

print(argspec)
# ArgSpec(args=['pos1', 'pos2', 'a', 'b', 'c'], varargs='args', keywords='kwargs', defaults=(1, 2, 3))

print(argspec.args)
# ['pos1', 'pos2', 'a', 'b', 'c']

print(argspec.args[-len(argspec.defaults):])
# ['a', 'b', 'c']

edited Aug 11 '12 at 13:43

answered Aug 11 '12 at 13:23

unutbu

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How can I make it give me the agrs only – user1513192 Aug 11 '12 at 13:24
3

`inspect.getargspec(thefunction).args` – jamylak Aug 11 '12 at 13:26
4

`argspec.args[-len(argspec.defaults):]` this should be accepted because it answers the question. – jamylak Aug 11 '12 at 13:38
No disrespect to the OP or Ashwini, but I agree this should really be the accepted answer for future references... – Jon Clements Aug 11 '12 at 13:55
1

`getargspec` has [been deprecated since v3](https://docs.python.org/3/library/inspect.html#inspect.getargspec), use `getfullargspec` instead. – nocibambi May 08 '21 at 09:57

Ashwini Chaudhary · Accepted Answer · 2013-11-03T16:48:27.290

1

Do you want something like this:

>>> def func(x,y,z,a=1,b=2,c=3):
    pass

>>> func.func_code.co_varnames[-len(func.func_defaults):]
('a', 'b', 'c')

edited Nov 03 '13 at 16:48

answered Aug 11 '12 at 13:27

Ashwini Chaudhary

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co_varnames is a wrong decision, it also holds non-keyword arguments and topic-starter wants only keyword arguments – Rostyslav Dzinko Aug 11 '12 at 13:28
2

@RostyslavDzinko yeah you're right, but the problem is `inspect.getargspec()` also returns non-keyword arguments. – Ashwini Chaudhary Aug 11 '12 at 13:32
@user1513192 This one is bad because it doesn't use inspect. It's better to use libraries in Python as they are designed for that use. – jamylak Aug 11 '12 at 13:35
4

@user1513192, this answer doesn't fix the problem you described. If it fits your needs - redescribe your problem (My upper comment shows why) – Rostyslav Dzinko Aug 11 '12 at 13:36
`def thefunction(foo, a=1,b=2,c=3): pass` Doesn't work. Should return `('a', 'b', 'c')` – jamylak Aug 11 '12 at 13:38
1

@jamylak used this because I haven't learned `inspect` yet and will surely learn it now. :) – Ashwini Chaudhary Aug 11 '12 at 13:51
1

In python 3 `func_code` has been renamed to `__code__`. – naught101 Nov 13 '14 at 05:26
`func.__code__.co_varnames` also returns local variables. – nocibambi May 08 '21 at 09:53

score 1 · Answer 3 · answered Aug 11 '12 at 13:28

1

You can do the following in order to get exactly what you are looking for.

>>> 
>>> def funct(a=1,b=2,c=3):
...     pass
... 
>>> import inspect
>>> inspect.getargspec(funct)[0]
['a', 'b', 'c']
>>>

answered Aug 11 '12 at 13:28

Alagappan Ramu

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Get Keyword Arguments for Function, Python

3 Answers3