Get a list/tuple/dict of the arguments passed to a function?
You can use locals()
to get a dict of the local variables in your function, like this:
def foo(a, b, c):
print locals()
>>> foo(1, 2, 3)
{'a': 1, 'c': 3, 'b': 2}
This is a bit hackish, however, as locals()
returns all variables in the local scope, not only the arguments passed to the function, so if you don't call it at the very top of the function the result might contain more information than you want:
def foo(a, b, c):
x = 4
y = 5
print locals()
>>> foo(1, 2, 3)
{'y': 5, 'x': 4, 'c': 3, 'b': 2, 'a': 1}
I would rather construct a dict or list of the variables you need at the top of your function, as suggested in the other answers. It's more explicit and communicates the intent of your code in a more clear way, IMHO.
Here's a function you can call to get the kwargs of the current function. Or if you want to use those lines directly in your own function instead of calling get_kwargs()
just remove the .f_back
import inspect
def get_kwargs():
frame = inspect.currentframe().f_back
keys, _, _, values = inspect.getargvalues(frame)
kwargs = {}
for key in keys:
if key != 'self':
kwargs[key] = values[key]
return kwargs
def test(x, y=100):
z = 7
print(get_kwargs())
test(5, 6)
# Output: {'x': 5, 'y': 6}
test(5)
# Output: {'x': 5, 'y': 100}
I would use *args
or **kwargs
and throw an exception if the arguments are not as expected
If you want to have the same errors than the ones checked by python you can do something like
def check_arguments(function_name,args,arg_names):
missing_count = len(arg_names) - len(args)
if missing_count > 0:
if missing_count == 1:
raise TypeError(function_name+"() missing 1 required positionnal argument: "+repr(arg_names[-1]))
else:
raise TypeError(function_name+"() missing "+str(missing_count)+" required positionnal argument: "+", ".join([repr(name) for name in arg_names][-missing_count:-1])+ " and "+repr(arg_names[-1]))
using with somethin like
def f(*args):
check_arguments("f",args,["a","b","c"])
#whatever you want
...
You can use the inspect module:
def foo(x):
return x
inspect.getargspec(foo)
Out[23]: ArgSpec(args=['x'], varargs=None, keywords=None, defaults=None)
This is a duplicate of this and this.