Getting list of parameter names inside python function

Possible Duplicate:
Getting method parameter names in python

Is there an easy way to be inside a python function and get a list of the parameter names?

For example:

def func(a,b,c):
    print magic_that_does_what_I_want()

>>> func()
['a','b','c']

Thanks

Answers:

Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

Well we don’t actually need inspect here.

>>> func = lambda x, y: (x, y)
>>> 
>>> func.__code__.co_argcount
2
>>> func.__code__.co_varnames
('x', 'y')
>>>
>>> def func2(x,y=3):
...  print(func2.__code__.co_varnames)
...  pass # Other things
... 
>>> func2(3,3)
('x', 'y')
>>> 
>>> func2.__defaults__
(3,)

For Python 2.5 and older, use func_code instead of __code__, and func_defaults instead of __defaults__.

Method 2

locals() returns a dictionary with local names:

def func(a,b,c):
    print(locals().keys())

prints the list of parameters. If you use other local variables those will be included in this list. But you could make a copy at the beginning of your function.

Method 3

If you also want the values you can use the inspect module

import inspect

def func(a, b, c):
    frame = inspect.currentframe()
    args, _, _, values = inspect.getargvalues(frame)
    print 'function name "%s"' % inspect.getframeinfo(frame)[2]
    for i in args:
        print "    %s = %s" % (i, values[i])
    return [(i, values[i]) for i in args]

>>> func(1, 2, 3)
function name "func"
    a = 1
    b = 2
    c = 3
[('a', 1), ('b', 2), ('c', 3)]

Method 4

import inspect

def func(a,b,c=5):
    pass

inspect.getargspec(func)  # inspect.signature(func) in Python 3

(['a', 'b', 'c'], None, None, (5,))

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0